Question

Q.29 Strength of caustic soda solution is 2g/litre. pH of this solution will be (log2 = 0.30)
(A) 11.9
(B) 9.7
(C) 10.8
(D) 12.7​

Answer 1

Answer:

d

Explanation:

as there is 2 gm of soda present so we can calculate no of moles by dividing molar mass with the mass present I.e. equals 0.05

so in a litre of solution conc will be 0.05.

as it'll break down to hydroxide and sodium ions. the conc reflects presence of hydroxide ion.

so by taking negative log of conc we'll get pOH as 1.3

as pH + pOH = 14

pH is 12.7.