Chapter 1 · Chemical Reactions and Equations

NCERT Exemplar Class 10 Science Chapter 1 Short Answer Questions

All 20 questions of NCERT Exemplar Class 10 Science Chapter 1 Short Answer Questions (Chemical Reactions and Equations), in the book's order, each with its answer and a step-by-step solution.

1. Q19
   Write the balanced chemical ​equations for the following reactions and identify the type of ​reaction in each case.

   1. (a)Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773K to form ammonia gas.
   2. (b)Sodium ​hydroxide solution is treated with acetic acid to form sodium acetate and water.
   3. (c)​Ethanol is warmed with ethanoic ​acid to form ethyl acetate in the presence of concentrated ${\text{H}}_2{\text{SO}}_4$.
   4. (d)Ethene is burnt in the presence of oxygen to form carbon dioxide, water and releases ​heat ​and light.
   Show answer

   The reactions are a combination, a neutralisation (double displacement), an esterification (double displacement) and a combustion.

   (a) ${\text{N}}_2(g)+3{\text{H}}_2(g)\underset{\text{catalyst}}{\overset{773\text{K}}{\to }}2{\text{NH}}_3(g)$ — combination reaction. (b) $\text{NaOH}(aq)+{\text{CH}}_3\text{COOH}(aq)\to {\text{CH}}_3\text{COONa}(aq)+{\text{H}}_2\text{O}(l)$ — double displacement, specifically a neutralisation. (c) ${\text{CH}}_3\text{COOH}+{\text{C}}_2{\text{H}}_5\text{OH}\stackrel{\text{conc. }{\text{H}}_2{\text{SO}}_4}{\to }{\text{CH}}_3{\text{COOC}}_2{\text{H}}_5+{\text{H}}_2\text{O}$ — esterification, a double displacement. (d) ${\text{C}}_2{\text{H}}_4(g)+3{\text{O}}_2(g)\to 2{\text{CO}}_2(g)+2{\text{H}}_2\text{O}(g)+\text{heat}+\text{light}$ — combustion, an oxidation reaction and exothermic.

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2. Q20
   Write the ​balanced chemical equations for ​the following reactions and identify the type of reaction ​in each ​case.

   1. (a)Thermit reaction, iron (III) oxide reacts with aluminium and ​gives molten iron and aluminium oxide.
   2. (b)Magnesium ribbon is burnt in an atmosphere of nitrogen ​gas ​to form solid magnesium nitride.
   3. (c)Chlorine gas is passed in an aqueous ​potassium iodide solution to form potassium chloride solution and solid iodine.
   4. (d)Ethanol is burnt in air to form carbon dioxide, water and releases heat.
   Show answer

   The reactions are displacement (a), combination (b), displacement (c) and combustion (d), each with its balanced equation.

   (a) ${\text{Fe}}_2{\text{O}}_3(s)+2\text{Al}(s)\to 2\text{Fe}(l)+{\text{Al}}_2{\text{O}}_3(s)+\text{heat}$ — displacement reaction, also a redox reaction and strongly exothermic. (b) $3\text{Mg}(s)+{\text{N}}_2(g)\to {\text{Mg}}_3{\text{N}}_2(s)$ — combination reaction. (c) ${\text{Cl}}_2(g)+2\text{KI}(aq)\to 2\text{KCl}(aq)+{\text{I}}_2(s)$ — displacement reaction. (d) ${\text{C}}_2{\text{H}}_5\text{OH}(l)+3{\text{O}}_2(g)\to 2{\text{CO}}_2(g)+3{\text{H}}_2\text{O}(g)+\text{heat}$ — combustion, an oxidation reaction and exothermic.

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3. Q21
   Complete the ​missing components/variables ​given ​as $x$ ​and $y$ ​in the ​following ​reactions

   1. (a)${\text{Pb(NO}}_3{)}_2(aq)+2\text{KI}(aq)\to {\text{PbI}}_2(x)+2{\text{KNO}}_3(y)$
   2. (b)$\text{Cu}(s)+2{\text{AgNO}}_3(aq)\to {\text{Cu(NO}}_3{)}_2(aq)+x(s)$
   3. (c)$\text{Zn}(s)+{\text{H}}_2{\text{SO}}_4(aq)\to {\text{ZnSO}}_4(x)+{\text{H}}_2(y)$
   4. (d)${\text{CaCO}}_3(s)\stackrel{x}{\to }\text{CaO}(s)+{\text{CO}}_2(g)$
   Show answer

   The missing items are (a) solid and aqueous, (b) silver, (c) aqueous and gas, (d) heat.

   (a) $x=(s)$ and $y=(aq)$, since lead iodide is the insoluble yellow precipitate while potassium nitrate stays dissolved. (b) $x=\text{Ag}$, so the equation reads $\text{Cu}(s)+2{\text{AgNO}}_3(aq)\to {\text{Cu(NO}}_3{)}_2(aq)+2\text{Ag}(s)$; copper displaces the less reactive silver. (c) $x=(aq)$ and $y=(g)$, since zinc sulphate remains in solution while hydrogen escapes as a gas. (d) $x=\text{heat}$, because calcium carbonate decomposes only on strong heating, at about $1200\text{K}$.

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4. Q22
   Which among the following changes are exothermic ​or endothermic ​in nature?

   1. (a)Decomposition ​of ferrous ​sulphate
   2. (b)Dilution of sulphuric acid
   3. (c)​Dissolution of sodium hydroxide ​in ​water
   4. (d)Dissolution of ammonium chloride in ​water
   Show answer

   Decomposition of ferrous sulphate and dissolution of ammonium chloride are endothermic; dilution of sulphuric acid and dissolution of sodium hydroxide are exothermic.

   (a) Endothermic — ferrous sulphate decomposes only while it is being heated, $2{\text{FeSO}}_4(s)\stackrel{\text{heat}}{\to }{\text{Fe}}_2{\text{O}}_3(s)+{\text{SO}}_2(g)+{\text{SO}}_3(g)$, so energy is absorbed. (b) Exothermic — diluting sulphuric acid releases a large amount of heat and the vessel becomes hot. (c) Exothermic — dissolving sodium hydroxide releases more energy on hydration than the lattice costs, so the solution warms. (d) Endothermic — dissolving ammonium chloride costs more energy than hydration returns, so heat is drawn from the water and the solution cools.

   Step-by-step solution →
5. Q23
   Identify the ​reducing ​agent ​in ​the following ​reactions

   1. (a)$4{\text{NH}}_3+5{\text{O}}_2\to 4\text{NO}+6{\text{H}}_2\text{O}$
   2. (b)${\text{H}}_2\text{O}+{\text{F}}_2\to \text{HF}+\text{HOF}$
   3. (c)${\text{Fe}}_2{\text{O}}_3+3\text{CO}\to 2\text{Fe}+3{\text{CO}}_2$
   4. (d)$2{\text{H}}_2+{\text{O}}_2\to 2{\text{H}}_2\text{O}$
   Show answer

   The reducing agents are ammonia, water, carbon monoxide and hydrogen; each is itself oxidised.

   (a) Ammonia, ${\text{NH}}_3$; (b) Water, ${\text{H}}_2\text{O}$; (c) Carbon monoxide, $\text{CO}$; (d) Hydrogen, ${\text{H}}_2$

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6. Q24
   Identify ​the oxidising ​agent ​(oxidant) in ​the ​following ​reactions

   1. (a)${\text{Pb}}_3{\text{O}}_4+8\text{HCl}\to 3{\text{PbCl}}_2+{\text{Cl}}_2+4{\text{H}}_2\text{O}$
   2. (b)$2\text{Mg}+{\text{O}}_2\to 2\text{MgO}$
   3. (c)${\text{CuSO}}_4+\text{Zn}\to \text{Cu}+{\text{ZnSO}}_4$
   4. (d)${\text{V}}_2{\text{O}}_5+5\text{Ca}\to 2\text{V}+5\text{CaO}$
   5. (e)$3\text{Fe}+4{\text{H}}_2\text{O}\to {\text{Fe}}_3{\text{O}}_4+4{\text{H}}_2$
   6. (f)$\text{CuO}+{\text{H}}_2\to \text{Cu}+{\text{H}}_2\text{O}$
   Show answer

   The oxidising agents in (a) to (f) are ${\text{Pb}}_3{\text{O}}_4$, ${\text{O}}_2$, ${\text{CuSO}}_4$, ${\text{V}}_2{\text{O}}_5$, ${\text{H}}_2\text{O}$ and $\text{CuO}$; each is reduced.

   (a) Red lead, ${\text{Pb}}_3{\text{O}}_4$; (b) Oxygen, ${\text{O}}_2$; (c) Copper sulphate, ${\text{CuSO}}_4$; (d) Vanadium(V) oxide, ${\text{V}}_2{\text{O}}_5$; (e) Water (steam), ${\text{H}}_2\text{O}$; (f) Copper(II) oxide, $\text{CuO}$

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7. Q25
   Write the balanced chemical equations for the following reactions

   1. (a)​Sodium carbonate on reaction with hydrochloric acid in equal molar concentrations ​gives ​sodium chloride ​and ​sodium hydrogencarbonate.
   2. (b)Sodium hydrogencarbonate on reaction with hydrochloric acid gives sodium ​chloride, water and liberates carbon dioxide.
   3. (c)Copper sulphate on treatment with ​potassium iodide ​precipitates cuprous iodide (${\text{Cu}}_2{\text{I}}_2$), liberates iodine gas and also forms potassium sulphate.
   Show answer

   The balanced equations are ${\text{Na}}_2{\text{CO}}_3+\text{HCl}\to \text{NaCl}+{\text{NaHCO}}_3$, ${\text{NaHCO}}_3+\text{HCl}\to \text{NaCl}+{\text{H}}_2\text{O}+{\text{CO}}_2$ and $2{\text{CuSO}}_4+4\text{KI}\to {\text{Cu}}_2{\text{I}}_2+{\text{I}}_2+2{\text{K}}_2{\text{SO}}_4$.

   (a) ${\text{Na}}_2{\text{CO}}_3(aq)+\text{HCl}(aq)\to \text{NaCl}(aq)+{\text{NaHCO}}_3(aq)$; (b) ${\text{NaHCO}}_3(aq)+\text{HCl}(aq)\to \text{NaCl}(aq)+{\text{H}}_2\text{O}(l)+{\text{CO}}_2(g)$; (c) $2{\text{CuSO}}_4(aq)+4\text{KI}(aq)\to {\text{Cu}}_2{\text{I}}_2(s)+{\text{I}}_2+2{\text{K}}_2{\text{SO}}_4(aq)$

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8. Q26
   A ​solution of potassium chloride when mixed with ​silver nitrate solution, ​an insoluble white ​substance is formed. Write ​the chemical reaction involved ​and also ​mention the type of the chemical reaction?
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   Potassium chloride and silver nitrate give white silver chloride and potassium nitrate: a double displacement (precipitation) reaction.

   $\text{KCl}(aq)+{\text{AgNO}}_3(aq)\to \text{AgCl}(s)+{\text{KNO}}_3(aq)$. The insoluble white substance is silver chloride, $\text{AgCl}$. The reaction is a double displacement reaction, and since an insoluble solid separates out it is also a precipitation reaction.

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9. Q27
   Ferrous sulphate decomposes with the evolution of ​a gas having ​a characteristic ​odour of burning ​sulphur. Write the ​chemical ​reaction involved and identify ​the type of reaction.
   Show answer

   Heating ferrous sulphate gives ferric oxide, sulphur dioxide and sulphur trioxide: a thermal decomposition reaction.

   $2{\text{FeSO}}_4(s)\stackrel{\text{Heat}}{\to }{\text{Fe}}_2{\text{O}}_3(s)+{\text{SO}}_2(g)+{\text{SO}}_3(g)$. The gas smelling of burning sulphur is sulphur dioxide. The reaction is a decomposition reaction, specifically a thermal decomposition, and it is endothermic. If the green crystals ${\text{FeSO}}_4\cdot 7{\text{H}}_2\text{O}$ are used, they first lose their water of crystallisation: ${\text{FeSO}}_4\cdot 7{\text{H}}_2\text{O}(s)\stackrel{\text{Heat}}{\to }{\text{FeSO}}_4(s)+7{\text{H}}_2\text{O}(g)$.

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10. Q28
    Why ​do ​fire flies ​glow at night?
    Show answer

    A protein pigment in the abdomen is oxidised by air with an enzyme, and the energy is released as light (bioluminescence).

    Fire flies glow because of a chemical reaction going on inside them. Their abdomen contains a protein pigment which is oxidised by the oxygen of the air in the presence of an enzyme, and the energy released by this oxidation is given out as visible light rather than as heat. It is therefore an oxidation reaction accompanied by the emission of light — chemiluminescence, or, since it takes place in a living organism, bioluminescence. Because the reaction needs oxygen, the insect can switch the glow on and off by controlling the air reaching those cells.

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11. Q29
    Grapes hanging on the plant ​do not ​ferment but after being plucked from the plant can be fermented. ​Under ​what ​conditions do ​these grapes ferment? Is it ​a chemical or ​a physical change?
    Show answer

    Plucked grapes ferment given yeast, sugar, moisture, moderate warmth and no air; it is a chemical change, since new substances form.

    Grapes ferment once they have been plucked, because the fruit is then no longer protected by the living plant and the micro-organisms that live on the skin can reach the sugary juice. The conditions needed are the presence of yeast, a supply of sugar and moisture, a moderately warm temperature, and the absence of air. Under these conditions the glucose is broken down: ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\stackrel{\text{yeast}}{\to }2{\text{C}}_2{\text{H}}_5\text{OH}+2{\text{CO}}_2$. It is a chemical change, because new substances (ethanol and carbon dioxide) are formed and the grape juice cannot be recovered from them.

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12. Q30
    Which ​among the following ​are physical or chemical ​changes?

    1. (a)Evaporation of petrol
    2. (b)Burning ​of Liquefied Petroleum Gas ​(LPG)
    3. (c)Heating of an iron rod ​to red hot.
    4. (d)Curdling of ​milk
    5. (e)Sublimation of solid ammonium chloride
    Show answer

    Evaporation of petrol, heating an iron rod and sublimation of ammonium chloride are physical changes; burning LPG and curdling of milk are chemical.

    (a) Physical change — only the state of the petrol alters, and condensing the vapour gives the petrol back; (b) Chemical change — the fuel is converted into carbon dioxide and water with the release of heat and light, and cannot be recovered; (c) Physical change — the rod glows because it is hot, but it is still iron and returns to normal on cooling; (d) Chemical change — bacteria turn the lactose into lactic acid and the milk sets as curd, which cannot be turned back into milk; (e) Physical change — sublimation is a change of state, and the ammonium chloride re-forms unchanged on cooling.

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13. Q31
    During the reaction ​of some metals with dilute ​hydrochloric acid, following observations were made.

    1. (a)Silver metal does not show ​any change
    2. (b)The temperature of the reaction mixture rises when aluminium (Al) is added.
    3. (c)The ​reaction ​of sodium ​metal is found to be highly explosive
    4. (d)Some bubbles of a gas are seen ​when lead (Pb) is reacted with the acid. Explain these observations giving suitable ​reasons.
    Show answer

    Silver is below hydrogen and does not react; aluminium, sodium and lead are above it and displace hydrogen at different rates.

    (a) Silver lies below hydrogen in the reactivity series, so it cannot displace hydrogen from dilute hydrochloric acid and no reaction occurs; (b) Aluminium lies well above hydrogen and displaces it readily, and since the reaction is exothermic the temperature of the mixture rises: $2\text{Al}(s)+6\text{HCl}(aq)\to 2{\text{AlCl}}_3(aq)+3{\text{H}}_2(g)$; (c) Sodium lies far above hydrogen, so the reaction is both very fast and strongly exothermic — so much heat is released so quickly that the hydrogen produced catches fire and the reaction becomes explosive: $2\text{Na}(s)+2\text{HCl}(aq)\to 2\text{NaCl}(aq)+{\text{H}}_2(g)$; (d) Lead lies only just above hydrogen, so it does displace hydrogen but slowly, and the sparingly soluble lead chloride formed coats the metal and slows it further, so only a few bubbles are seen: $\text{Pb}(s)+2\text{HCl}(aq)\to {\text{PbCl}}_2(s)+{\text{H}}_2(g)$.

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14. Q32
    A substance X, which is an oxide of a group 2 ​element, is ​used ​intensively in the cement industry. This element is present in bones ​also. On treatment with water it forms ​a solution which turns red litmus blue. Identify X ​and also write the chemical reactions involved.
    Show answer

    X is calcium oxide ($\text{CaO}$); with water it forms calcium hydroxide, a base that turns red litmus blue.

    X is calcium oxide, $\text{CaO}$, commonly called quicklime. Calcium is a group 2 element, calcium compounds make up the mineral part of bone, and lime is used in vast quantity in the cement industry. With water it combines to give calcium hydroxide, releasing much heat: $\text{CaO}(s)+{\text{H}}_2\text{O}(l)\to {\text{Ca(OH)}}_2(aq)+\text{heat}$ — a combination reaction, and exothermic. The calcium hydroxide gives hydroxide ions in solution, ${\text{Ca(OH)}}_2(aq)\to {\text{Ca}}^{2+}(aq)+2{\text{OH}}^{-}(aq)$, which is why the solution is basic and turns red litmus blue.

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15. Q33
    Write a balanced ​chemical equation for each of the following ​reactions and also classify ​them.

    1. (a)Lead acetate solution is treated with dilute hydrochloric acid to form lead chloride and acetic acid solution.
    2. (b)A ​piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.
    3. (c)Iron (III) oxide on ​heating with carbon monoxide gas reacts to form ​solid iron and liberates carbon dioxide gas.
    4. (d)Hydrogen sulphide gas reacts ​with oxygen gas to form solid sulphur and ​liquid water.
    Show answer

    The reactions are classified as double displacement (a), displacement (b) and redox (c) and (d), each with its balanced equation.

    (a) ${\text{Pb(CH}}_3{\text{COO)}}_2(aq)+2\text{HCl}(aq)\to {\text{PbCl}}_2(s)+2{\text{CH}}_3\text{COOH}(aq)$ — a double displacement reaction; (b) $2\text{Na}(s)+2{\text{C}}_2{\text{H}}_5\text{OH}(l)\to 2{\text{C}}_2{\text{H}}_5\text{ONa}+{\text{H}}_2(g)$ — a displacement reaction; (c) ${\text{Fe}}_2{\text{O}}_3(s)+3\text{CO}(g)\stackrel{\text{Heat}}{\to }2\text{Fe}(s)+3{\text{CO}}_2(g)$ — a redox reaction, in which the iron(III) oxide is reduced and the carbon monoxide oxidised; (d) $2{\text{H}}_2\text{S}(g)+{\text{O}}_2(g)\to 2\text{S}(s)+2{\text{H}}_2\text{O}(l)$ — a redox reaction, the oxidation of hydrogen sulphide.

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16. Q34
    Why do ​we store silver chloride ​in ​dark ​coloured ​bottles?
    Show answer

    Silver chloride decomposes in light into silver and chlorine; a dark bottle absorbs the light and prevents this.

    Silver chloride decomposes in sunlight into silver and chlorine, $2\text{AgCl}(s)\stackrel{\text{sunlight}}{\to }2\text{Ag}(s)+{\text{Cl}}_2(g)$, which is why a white sample left in the light slowly turns grey — the grey being finely divided metallic silver. This is a photochemical decomposition reaction, and light is what supplies the energy for it. A dark coloured bottle absorbs the light before it can reach the solid, so the decomposition cannot take place and the silver chloride keeps its composition.

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17. Q35
    Balance ​the ​following ​chemical equations and ​identify the type ​of chemical ​reaction.

    1. (a)$\text{Mg}(s)+{\text{Cl}}_2(g)\to {\text{MgCl}}_2(s)$
    2. (b)$\text{HgO}(s)\stackrel{\text{Heat}}{\to }\text{Hg}(l)+{\text{O}}_2(g)$
    3. (c)$\text{Na}(s)+\text{S}(s)\stackrel{\text{Fuse}}{\to }{\text{Na}}_2\text{S}(s)$
    4. (d)${\text{TiCl}}_4(l)+\text{Mg}(s)\to \text{Ti}(s)+{\text{MgCl}}_2(s)$
    5. (e)$\text{CaO}(s)+{\text{SiO}}_2(s)\to {\text{CaSiO}}_3(s)$
    6. (f)${\text{H}}_2{\text{O}}_2(l)\stackrel{\text{UV}}{\to }{\text{H}}_2\text{O}(l)+{\text{O}}_2(g)$
    Show answer

    Reactions (a), (c) and (e) are combination, (b) and (f) are decomposition, and (d) is displacement.

    (a) $\text{Mg}(s)+{\text{Cl}}_2(g)\to {\text{MgCl}}_2(s)$ — already balanced; a combination reaction; (b) $2\text{HgO}(s)\stackrel{\text{Heat}}{\to }2\text{Hg}(l)+{\text{O}}_2(g)$ — a decomposition reaction, thermal decomposition; (c) $2\text{Na}(s)+\text{S}(s)\stackrel{\text{Fuse}}{\to }{\text{Na}}_2\text{S}(s)$ — a combination reaction; (d) ${\text{TiCl}}_4(l)+2\text{Mg}(s)\to \text{Ti}(s)+2{\text{MgCl}}_2(s)$ — a displacement reaction; (e) $\text{CaO}(s)+{\text{SiO}}_2(s)\to {\text{CaSiO}}_3(s)$ — already balanced; a combination reaction; (f) $2{\text{H}}_2{\text{O}}_2(l)\stackrel{\text{UV}}{\to }2{\text{H}}_2\text{O}(l)+{\text{O}}_2(g)$ — a decomposition reaction, photochemical decomposition.

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18. Q36
    A magnesium ribbon is ​burnt ​in oxygen to give a white ​compound X accompanied by emission of light. ​If the burning ribbon is now placed in ​an ​atmosphere of nitrogen, it continues to burn and forms a compound Y.

    1. (a)​Write the chemical formulae of X and Y.
    2. (b)Write a balanced ​chemical equation, when X is dissolved in water.
    Show answer

    X is $\text{MgO}$ and Y is ${\text{Mg}}_3{\text{N}}_2$; $\text{MgO}$ dissolves in water to give magnesium hydroxide, ${\text{Mg(OH)}}_2$.

    (a) $X=\text{MgO}$, magnesium oxide, the white compound formed in oxygen; $Y={\text{Mg}}_3{\text{N}}_2$, magnesium nitride, formed when the burning ribbon is placed in nitrogen. (b) $\text{MgO}(s)+{\text{H}}_2\text{O}(l)\to {\text{Mg(OH)}}_2(aq)$ — magnesium oxide dissolves in water to give magnesium hydroxide, a combination reaction whose product makes the water faintly basic.

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19. Q37
    Zinc ​liberates ​hydrogen ​gas ​when reacted with dilute hydrochloric acid, whereas copper ​does ​not. Explain why?
    Show answer

    Zinc lies above hydrogen and displaces it from the acid; copper lies below hydrogen, so it cannot and no gas is liberated.

    Zinc lies above hydrogen in the reactivity series, so it gives up its electrons more readily than hydrogen does. It can therefore hand them to the hydrogen ions of the acid, taking their place in the salt and setting hydrogen gas free: $\text{Zn}(s)+2\text{HCl}(aq)\to {\text{ZnCl}}_2(aq)+{\text{H}}_2(g)$. Copper lies below hydrogen in the series, so it holds its electrons more tightly than hydrogen does and cannot give them to the hydrogen ions. No electron transfer is possible, so copper does not displace hydrogen from dilute hydrochloric acid and no gas is liberated.

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20. Q38
    A silver article generally turns black when kept in the open for ​a few ​days. The article when rubbed with ​toothpaste again starts ​shining.

    1. (a)Why do silver articles turn black when kept in the open ​for a few days? Name the phenomenon involved.
    2. (b)Name ​the black ​substance formed and give its ​chemical formula.
    Show answer

    Silver reacts with hydrogen sulphide of the air to form black silver sulphide, ${\text{Ag}}_2\text{S}$, a corrosion called tarnishing.

    (a) Silver articles turn black because the silver at the surface is slowly attacked by the small amount of hydrogen sulphide present in the air, in the presence of oxygen, and becomes coated with a thin layer of a new compound: $4\text{Ag}(s)+2{\text{H}}_2\text{S}(g)+{\text{O}}_2(g)\to 2{\text{Ag}}_2\text{S}(s)+2{\text{H}}_2\text{O}(l)$. The phenomenon is corrosion — for silver it is usually called tarnishing. (b) The black substance is silver sulphide, formula ${\text{Ag}}_2\text{S}$. Rubbing with toothpaste, which is a mild abrasive, scrapes this thin layer away and exposes the bright silver beneath.

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