Question

Calculate the mass of $H_{2}O$ and $C_2{H}_{5}OH$ required to make 640 gm mixture having $X_{H_{2}O}$ and $X_{C_2{H}_{5}OH}$ equal to 0.5

• A. 640 gm, 640 gm
• B. 180 gm, 180 gm
• C. 180 gm, 460 gm
• D. 460 gm, 180 gm

Answer 1

The correct option is C

180 gm, 460 gm

It is given that

$X_{H_{2}O}=X_{C_2{H}_{5}OH}=0.5$

But $X_{H_{2}O}=\frac{Molesof{H}_{2}O}{Molesof{H}_{2}O+Molesof{C}_2{H}_{5}OH}=0.5$

$\Rightarrow$ Moles of $H_{2}O$ = Moles of $C_2{H}_{5}OH$
1 mole of $H_{2}O$ = 18 gm
1 mole of $C_2{H}_{5}OH$ = 46 gm
This gives 64 gm
$\therefore$for 640 gm, we need 10 moles each $\Rightarrow$ 180 gm $H_{2}O$ and 460 gm $C_2{H}_{5}OH$