Question

Justin needs 15 L of a 22% sodium hydroxide (NaOH) solution for an

experiment he is running. Unfortunately, the laboratory only has 30% NaOH and 5%
NaOH in stock. How many liters of each sodium hydroxide solution does Justin need to
mix to make the 15 L for his experiment?

Answer 1

Answer: Quantity of 30% NaOH = 10.2 L .

Quantity of 5% NaOH =4.8L .

Explanation:

Let x = Quantity of 30% NaOH .

y= Quantity of 5% NaOH .

As per given, x+y= 15 (i)[total quantity]

0.30x+0.05y=0.22(15) [quantity of NaOH]

⇒ 0.30x+0.05y=3.3 (ii)

Multiply 0.30 to (i), we get

0.30x+0.30y= 4.5 (iii)

Eliminate (ii) from (iii)

0.25y=1.2

y= 4.8 [divide both sides by 0.25]

put this in (i), we get

x+4.8=15

⇒ x= 15-4.8 = 10.2

Hence, Quantity of 30% NaOH = 10.2 L .

Quantity of 5% NaOH =4.8L .