Mr of Acid getting wrong answer
The concentration of your acid is given as a mass concentration. 

Without knowing the molar mass, the molar concentration and the amount of substance in a volume of $15~\mathrm{cm}^{-3}$ are not accessible.

However, knowing that 

$\mathrm{1~L = 1~dm^{-3} = 1000~cm^{-3}}$ 

and therefore 

$15~\mathrm{cm}^{-3} = 0.015~\mathrm{dm}^{-3}$

the mass of the acid (in $15~\mathrm{cm}^{-3}$) is given as

$m = 10.95~\mathrm{g\,dm^{−3}\cdot0.015~\mathrm{dm}^{-3} = 0.16425~g}$