Question
Question: Common salt besides being used in kitchen can also be used as the raw material for making i) Washi...
Common salt besides being used in kitchen can also be used as the raw material for making
i) Washing soda
ii) Bleaching powder
iii) Baking soda
iv)Slaked lime
A) (i) and (ii)
B) (i),(ii) and (iv)
C) (i) and (iii)
D) (i),(iii) and (iv)
Solution
Common salt is the chemical compound with the formula NaCl. Washing soda is the common name for sodium carbonate,bleaching powder is the common name for calcium hypochlorite. Baking soda has the chemical name sodium hydrogen carbonate and the chemical name for slaked lime is Calcium hydroxide.
Complete answer:
So in the question it is asked that the common salt which is used in the kitchen is as the raw materials for which compounds in the given options.
So this question is basically discussing the manufacturing of the given products.
We know that common salt has its chemical name, sodium chloride which plays a major role for enhancing the taste and one essential compound which we find in our day to day life.
NaCl is produced in massive quantities by the evaporation of seawater.It is also obtained by the mining of rock salt.It is also synthesized by carrying out reaction between sodium and chloride.
So now let's discuss the production of the above compounds given.
i) Washing soda
It is also called as sodium carbonate (Na2CO3). The sodium carbonate is prepared by Solvay process.
The sodium bicarbonate is prepared by the Solvay process.
In the Solvay process,NaCl, NH3,CO2 and H2O is added and this on reaction gives sodium hydrogen carbonate and ammonium chloride.
And the sodium hydrogen carbonate which is precipitated in the solution is collected,filtered and is heated to get sodium carbonate.
NaCl+NH3+CO2+H2O→NaHCO3↓+NH4Cl
2NaHCO3ΔNa2CO3+H2O+CO2
ii) Bleaching powder
Bleaching powder is the common name for Calcium hypochlorite.It is prepared from Calcium hydroxide.
The milk of lime ie Ca(OH)2 is treated with chlorine and it gives calcium hypochlorite which is called as the bleaching powder.
Calcium chloride is obtained as the side product.
2Ca(OH)2+2Cl2→CaCl2+Ca(OCl)2+2H2O
The Ca(OCl)2formed is the bleaching powder.
iii) Baking soda
Baking soda is the common name for sodium hydrogen carbonate or sodium bicarbonate (NaHCO3).
The NaHCO3 is produced by the solvay process. The NaHCO3 is an intermediate formed during the preparation of sodium carbonate.
Hence here also NaCl is one of the raw materials used.
However, NaHCO3 which is formed possess low solubility hence is precipitated out and filtered.
NaCl+NH3+CO2+H2O→NaHCO3↓+NH4Cl
Therefore we use NaCl as a raw material in the preparation of washing soda and baking soda.
Hence the correct answer for the question is option (C).
Note:
The washing soda is also called soda ash or soda crystals. In massive amounts,the sodium bicarbonate is produced from sodium carbonate. In the Leblanc process for the production of sodium carbonate also, NaCl is used as the raw materials.