35. (a) In one of the industrial processes used for manufacture of sodium hydroxide, a gas X is formed as a by-product. The gas X reacts with lime water to give a compound Y which is used as a bleaching agent in the chemical industry. Identify X and Y giving the chemical equation of the reactions involved. (2 marks) (b) For making cake, baking powder is taken. If at home your mother uses baking soda instead of baking powder in cake, (3 marks) (i) how will it affect the taste of the cake and why? (ii) how can baking soda be converted into baking powder? (iii) what is the role of tartaric acid added to baking soda?
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Answer:
Sodium chloride is used for manufacture of sodium hydroxide which is called chloralkali process. In this process chlorine and hydrogen gas are formed as byproducts along with sodium hydroxide. Chlorine gas gives bleaching power when reacts with lime water and used as bleaching agent in chemical industries.
2NaCl(aq)+2H2O(l)→2NaOH(aq)+Cl2 (g)+H2(g).
X→Cl2 (Chlorine gas)
Ca(OH)2+Cl2⟶CaOCl2+H2O
Therefore,
The gas X is chlorine.
Compound Y is calcium oxychloride which is commonly known as bleaching powder and used as bleaching agent in chemical industries.