Question

25 ml of 3.00 M HNO3 is mixed with 75 ml of 4.00 M HNO3. If the volumes are additive, then the molarity of the final mixture would be ?​

Answer 1

Given that,

Volume $V_{1}=25\ ml$

Molarity $M_{1}=3\ M$

Volume $V_{2}=75\ ml$

Molarity $M_{2}=4\ M$

If the volumes are additive, then the molarity of final mixture will be

$M_{1}=M_{2}=M$

We need to calculate the molarity of final mixture

Using formula of molarity

$M=\dfrac{M_{1}V_{1}+M_{2}V_{2}}{V_{1}+V_{2}}$

Put the value into the formula

$M=\dfrac{25\times3+75\times4}{25+75}$

$M=3.75\ M$

Hence, The molarity of final mixture is 3.75 M.