Question

the concentration of a 200 g salt soln is 10% if 20 g more water is added what will the concentration become

Answer 1

ANSWER:

• The new concentration of solution = 0.91 %.

GIVEN:

• Weight of solute = 200 g.

• The concentration of salt solution is 10%.

• 20 g more water is added.

TO FIND:

• The new concentration of solution.

EXPLANATION:

Water acts as the solvent as it is given that 20 g more water is added.

Salt acts as solute because it is in lesser amount by weight when compared to water.

$\boxed{\large{\bold{Weight \ \% = \dfrac{weight\ of\ solute}{weight\ of\ solution}\times 100}}}$

Weight percentage = 10 %

Weight of solute = 20 g

Weight of solution = Weight of solute + Weight of solvent

Let Weight of solvent be x

Weight of solution = (20 + x ) g

$\sf 10 = \dfrac{20}{20 + x}\times 100$

$\sf 1 = \dfrac{20}{20 + x}\times 10$

$\sf 20 + x = 200$

$\sf x = 180 \ g$

Weight of solvent(water) = 180 g

When 20 g more water is added.

New Weight of solvent(water) = 200 g

$\boxed{\large{\bold{Weight \ \% = \dfrac{weight\ of\ solute}{weight\ of\ solution}\times 100}}}$

Weight of solution = 200 + 20 = 220 g

Weight of solute = 20 g

$\sf Weight \ \% = \dfrac{20}{220}\times 100$

$\sf Weight \ \% = \dfrac{20}{22}\times 10$

$\sf Weight \ \% = \dfrac{1}{11}\times 10$

$\sf Weight \ \% = 0.91\ \%$

HENCE THE CONCENTRATION WILL BE 0.91 %.