Question

$10$ mL of $aM$ solution of $HCl$ is mixed with $40$ mL of $1M$ $HCl$ to produce a mixture of $2M$. The value of $a$ is:

Answer 1

As we know,
$M_1{V}_1+M_2{V}_2=MV$
$10\times a+40\times 1=2\times 50$
$a=6$

Hence, the value of $a$ is $6$.