Question

An analysis showed there is 0.001 mol/L OH in a NaOH

Answer 1

40 ppm of NaOH

Explanation:

ppm is nothing but the parts per million and it is represented as 1 mg solute per kg of solution.

Here, number of moles of solute (NaOH) can be found as 0.001 mol / L, so we can find the amount of solute as,

Moles = $\frac{mass of the solute }{ molar mass}$

0.001 mol / L = $\frac{ mass of the solute}{40 g/ mol}$

0.001 × 40 = 0.04 g of solute

1 g = 1000 mg  

0.04 g = 40 mg

In 1 kg of solution 40 mg of solvent is present.

So the concentration of NaOH is 40 ppm.