Question

A is a solution of hcl containing 7.30gdm^-3 and B is a solution of X2CO3 containing 10.6gdm^-3.calculate the concentration of A in Moldm^-3

Answer 1

This seems like an odd question to me. All of that information about B but no question about it.
mols HCl = grams/molar mass = ?
Since that is g/dm^3 that gives you mols/dm^3

Answer 2

molar mass