Solution A contains 7g/L MgCl₂ and solution B contains 7g/L of NaCl. At room temperature, the osmotic pressure of

Osmotic presire ($\mathrm{\pi }$)= i CRT 

i = van't Hoff factor. 

$\mathrm{\pi }\propto \mathrm{C}$

concentration of NaCl solution = $\frac{7}{58.5}= 0.119M$

concentration of MgCl₂= $\frac{7}{95}=0.074M$

The ions furnished by NaCl is more than in MgCl₂.

The solution of NaCl(B) has more osmotic pressure than solution (A)  MgCl₂.