How much water should I add to 30 g of a 20% sodium hydroxide solution to lower its concentration to 15%?

bystudin | May 28, 2020 | Education

ω = m (substance) / m (solution), we find the mass of alkali m = 30 * 0.2 = 6 g
ω = m (substance) / m (solution), let x be the mass of water to be added, then:
0.15 = 6 / (30 + x)
4,5 + 0,15x = 6
x = 10 g

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