Question

1270
12
How many grams of KCI would have to be dissolved in
60 gm H2O to give 20% by wt. of KCl solution ?
(1) 15 gm
(2) 1.5 gm
(3) 11.5 gm
(4) 31.5 gm​

Answer 1

answer is 15gm of kcl solution

Answer 2

Answer:

Option 1: 15 gm

Explanation:

Given:

• Weight of H₂O = 60 gm
• % weight of KCl in the solution = 20 %

To Find:

• Grams of KCl in the solution

Solution:

Given that the mass% of the compound in the solution is 20%.

We know that mass% is given by,

$\boxed{\sf Mass\: \%=\dfrac{Mass\:of\:the\:component\:in\:the\:solution}{Total\:mass\:of\:the\:solution} \times 100}$

Here component is KCl

Let us assume that m gm of KCl is present in the solution.

Hence mass of the total solution = m + 60 gm

Substituting in the above equation,

$\sf 20=\dfrac{m}{m+60} \times 100$

$\sf \dfrac{m}{m+60} =0.2$

$\sf m=0.2(m+60)$

$\sf m-0.2\:m=12$

$\sf 0.8\:m=12$

$\sf m=15\:gm$

Hence 15 gm of KCl is to be dissolved in the solution.

Therefore option 1 is correct.