Solutions of Chemical Reactions and Equations (Page No - 49) - Chemistry Lakhmir Singh, Class 10 | Extra Documents, Videos & Tests for Class 10 PDF Download

Question 58:
When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out.
(a) Name the iron salt.
(b) Name the type of reaction that takes place during the heating of iron salt.
(c) Write a chemical equation for the reaction involved.
Solution :
(a) Ferrous sulphate.
(b) Decomposition reaction.
(c)

Question 59:
A colourless lead salt, when heated, produces a yellow residue and brown fumes.
(a) Name the lead salt.
(b) Name the brown fumes.
(c) Write a chemical equation of the reaction involved.
Solution :
(a) Lead nitrate.
(b) Nitrogen dioxide.
(c)

Question 60:
When hydrogen burns in oxygen, water is formed and when water is electrolysed, then hydrogen and oxygen are produced. What type of reaction takes place :
(a) in the first case ?
(b) in the second case ?
Solution :
(a) Combination reaction.
(b) Decomposition reaction.

Question 61:
A strip of metal X is dipped in a blue coloured salt solution YSO₄. After some time, a layer of metal Y from the salt solution is formed on the surface of metal strip X. Metal X is used in galvanisation whereas metal Y is used in making electric wires. Metal X and metal Y together form an alloy Z.
(a) What could metal X be ?
(b) What could metal Y be ?
(c) Name the metal salt YSO₄.
(d) What type of chemical reaction takes place when metal X reacts with salt solution YSO₄ ? Write the equation of the chemical reaction involved.
(e) Name the alloy Z.
Solution :
(b) Copper (Cu)
(c) Copper sulphate (CuSO₄)
(d) Displacement reaction;
CuSO₄ (aq) + Zn (s)
ZnSO₄ (aq) + Cu (s)
(e) Brass

Question 62:
When a black metal compound XO is heated with a colourless gas Y₂, then metal X and another compound Y₂O are formed. Metal X is red-brown in colour which does not react with dilute acids at all. Gas Y₂ can be prepared by the action of a dilute acid on any active metal. The compound Y₂O is a liquid at room temperature which can turn anhydrous copper sulphate blue.
(a) What do you think is metal X ?
(b) What could be gas Y₂ ?
(c) What is compound XO ?
(d) What is compound Y₂O?
(e) Write the chemical equation of the reaction which takes place on heating XO with Y₂.
(f) What type of chemical reaction is illustrated in the above equation ?
Solution :
(a) Copper (Cu)
(b) Hydrogen (H₂)
(c) Copper oxide (CuO)
(d) Water (H₂O)
(e) CuO + H₂
Cu + H₂O
(f) Displacement reaction (which is also a redox reaction).

Question 63:
A metal X forms a water soluble salt XNO₃ . When an aqueous solution of XNO₃ is added to common salt solution, then a white precipitate of compound Y is formed along with sodium nitrate solution. Metal X is said to be the best conductor of electricity and it does not evolve hydrogen when put in dilute hydrohloric acid.
(a) What is metal X ?
(b) What is salt XNO₃ ?
(c) Name the compound Y.
(d) Write the chemical equation of the reaction which takes place on reacting XNO₃ solution and common salt solution giving the physical states of all the reactants and products.
(e) What type of chemical reaction is illustrated by the above equation ?
Solution :
Silver (Ag)
(b) Silver nitrate (AgNO₃)
(c) Silver chloride (AgCl)
(d) AgNO₃(aq) + NaCl (aq)—–>AgCl (s) + NaNO₃ (aq)
(e) Double displacement reaction.