Solutions of Chemical Reactions and Equations (Page No - 50) - Chemistry Lakhmir Singh, Class 10 | Extra Documents, Videos & Tests for Class 10 PDF Download

Question 64:
Two metals X and Y form the salts XSO₄ and Y₂SO₄, respectively. The solution of salt XSO₄ is blue in colour whereas that of Y₂SO₄ is colourless. When barium chloride solution is added to XSO₄ solution, then a white precipitate Z is formed along with a salt which turns the solution green. And when barium chloride solution is added to Y₂SO₄ solution, then the same white precipitate Z is formed along with colourless common salt solution.
(a) What could the metals X and Y be ?
(b) Write the name and formula of salt XSO₄.
(c) Write the name and formula of salt Y₂SO₄.
(d) What is the name and formula of white precipitate Z ?
(e) Write the name and formula of the salt which turns the solution green in the first case.
Solution :
(a) Metal X : Copper; Metal Y : Sodium
(b) Copper sulphate, CuSO₄
(c) Sodium sulphate, Na₂SO₄
(d) Barium sulphate, BaSO₄
(e) Copper chloride, CuCl₂

Question 65:
A red-brown metal X forms a salt XSO₄. When hydrogen sulphide gas is passed through an aqueous solution of XSO₄, then a black precipitate of XS is formed alongwith sulphuric acid solution.
(a) What could the salt XSO₄ be ?
(b) What is the colour of salt XSO₄ ?
(c) Name the black precipitate XS.
(d) By using the formula of the salt obtained in (a) above, write an equation of the reaction which takes place when hydrogen sulphide gas is passed through its aqueous solution.
(e) What type of chemical reaction takes place in this case ?
Solution :
(a) Copper sulphate.
(b) Blue colour.
(c) Copper sulphide.
(d) CuSO₄ (aq) + H₂S (g)—–>CuS (s) + H₂SO₄ (aq)
(e) Double displacement reaction.

Question 66:
When a strip of red-brown metal X is placed in a colourless salt solution YNO₃ then metal Y is set free and a blue coloured salt solution X(NO₃)₂ is formed. The liberated metal Y forms a shining white deposit on the strip of metal X.
(a) What do you think metal X is ?
(b) Name the salt YNO₃.
(c) What could be metal Y ?
(d) Name the salt X(NO₃)₂.
(e) What type of reaction takes place between metal X and salt solution YNO₃ ?
Solution :
(a) Copper.
(b) Silver nitrate.
(c) Silver.
(d) Copper nitrate.
(e) Displacement reaction.

Question 67:
A metal salt MX when exposed to light splits up to form metal M and a gas X₂. Metal M is used in making ornaments whereas gas X₂ is used in making bleaching powder. The salt MX is itself used in black and white photography.
(a) What do you think metal M is ?
(b) What could be gas X₂ ?
(c) Name the metal salt MX.
(d) Name any two salt solutions which on mixing together can produce a precipitate of salt MX.
(e) What type of chemical reaction takes place when salt MX is exposed to light ? Write the equation of the reaction.
Solution :
(a) Silver.
(b) Chlorine.
(c) Silver chloride.
(d) Silver nitrate and Sodium chloride.
(e) Decomposition reaction;