Question

Aluminium sulphate (X) is slightly insoluble in water. It is converted into soluble sodium sulphate by using ${Na}_2{CO}_3$ in the preparation of sodium carbonate extract. Moles of (Y), required for complete conversion of 1 mole of (X) into soluble sulphate, is :

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is C 3

1 mole of (X) reacts with 3 moles of (Y) to form soluble sulphate.
$A{l}_2(S{O}_4{)}_3+3N{a}_{2}C{O}_3+x{H}_{2}O\to A{l}_2(S{O}_4{)}_3\cdot 3N{a}_{2}C{O}_3\cdot x{H}_{2}O$
It is a double salt.