JEE Main levelSingle correct optionDifficulty 2 of 3sb177
In the Solvay process, sodium hydrogencarbonate separates from the cold ammoniacal brine saturated with COX2 mainly because
Ait is completely insoluble in water at all temperatures
Bit is the only salt whose ions are present in the solution
Cit is the least soluble of the salts that can form in this solution under these conditions
Dit is formed as a gas that is trapped by brine
Answer: C
The ions NaX+, ClX−, NHX4X+ and HCOX3X− are all present. Of the four possible salts, NaHCOX3 has the lowest solubility in cold solution, so it crystallises while NHX4Cl stays dissolved. It is not completely insoluble.