Question

The molarity of a sulphuric acid sample having
density 2.12 g/mL and mass percentage 49% (w/w)
is equal to
(1) 18.8 M
(2) 10.6 M
(3) 16.8 M
(4) 21.1 M​

Answer 1

answer : option (2) 10.6M

explanation : density of sulphuric acid sample , d = 2.12 g/ml

mass percentage of sulphuric acid sample , % (w/W) = 49%

molar mass of sulphuric acid , M = 98 g/mol

[ chemical formula of sulphuric acid is H2SO4, so molar mass of H2SO4 = 2 × atomic mass of H + atomic mass of S + 4 × atomic mass of O

= 2 × 1 + 32 + 4 × 16 = 98 g/mol ]

so, molarity of sulphuric acid = d × 10 × %(w/W)/M

= 2.12 × 10 × 49/98

= 10.6 M

hence, molarity of sulphuric acid should be 10.6M.

therefore, option (2) 10.6M is correct choice.