Question

15. i. A chemical compound X is used in glass and soap industry. Identify the compound and give its Chemical formula.
ii. How many molecules of water of crystallization are present in compound X.
iii. How will you prepare the above compound starting from sodium chloride. write all relevant equation involved in the process​

Answer 1

Explanation:

(i) Sodium carbonate is a compound (X) which is used in glass and soap industry. Its chemical formula is Na2CO3.

(ii)Ten molecules of water of crystallisation (i.e.10H2O) are present in this compound.

(iii) When NaCl is reacted with ammonia, carbon-dioxide and oxygen, sodium hydrogen carbonate and ammonium chloride are obtained. When the obtained sodium hydrogen carbonate is heated sodium carbonate is obtained along with water and carbon-dioxide.

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Answer 2

i. The compound (X) is washing soda i.e., Sodium carbonate which is used in glass and soap industry. Its chemical formula is Na₂CO₃.10H₂0

ii. Ten molecules of water of crystallisation are present in this compound.

iii. Ammonia and carbon dioxide gas in passed through brine (or concentrated sodium chloride solution) then a mixture of NaHCO₃ and NH₄Cl is formed.

$\sf NaCl (s) + NH_3 (g) + CO_2 (g) + H_2O (l) + CO_2 (g) \to NaHCO_3 (s) + NH_4Cl (g)$

On heating NaHCO₃, sodium carbonate is formed releasing water and carbon dioxide.

$\sf 2NaHCO_3 (s) \to Na_2CO_3 (s) + H_2O (l) + CO_2(g)$

Soda ash is dissolved in water. The solution is recrystallization and upon cooling, it gives hydrated Sodium carbonate which is also known as washing soda.

$\sf Na_2CO_3 (s) + 10H_2O (l) \to Na_2CO_3.10H_2O$