Question

1.25 M if solution a is mixed with.75molar of solution b in such away that obtained solution is 1 liter and its molarity is 1 molar find the volume of solution a and b​

Answer 1

We know that

$\boxed{\red{\bold{\sf{\Large{Molarity=\dfrac{No.\:of\:moles}{Volume(in\:\:L)}}}}}}$

$\rule{200}{2}$

Hence,

For Solution A

$M_A=\dfrac{No.\:of\:moles}{V_A} =1.25$

$\rule{200}{2}$

For solution B

$M_2=\dfrac{No.\:of\:moles}{V_B}0.75$

$\rule{200}{2}$

For Resultant solution:-

$M_R=\dfrac{No.\:of\:moles}{V_A+V_B}=1$

$\rule{200}{2}$

As per question :-

Resultant volume = 1 Litre

$V_A+V_B=1\\ \\ \\V_B=1-V_A$

$\rule{200}{2}$

Now ,

Number of moles remains constant.

So,

$M_AV_A+M_BV_B=M_RV_R$

Therefore :-

$1.25V_A+0.75(1-V_A)=1\\ \\ \\1.25V_A-0.75V_A+0.75=1\\ \\ \\0.5V_A=0.25\\ \\ \\V_A=\dfrac{0.25}{0.5}=0.5$

$\rule{200}{2}$

Therefore,

Volume of solution A = 500 ml

Volume of solution B= 1000-500 = 500ml