Question

Question no 7 please

Answer 1

a
one mole of h3po3 reacts with 3 moles of koh
mili moles of h3po3 = 0.1×20
milk moles of koh req=3x0.1×20
volume=3×0.1×20/0.1=60

Answer 2

One mole of Phosphorous acid (H₃PO₃) when dissociates in water gives 2 moles of H⁺ ions. So, its n-factor = 2

Normality, N₁ = Molarity x n-factor = 0.1 x 2 = 0.2

Given that Volume, V₁ = 20 ml

Also, 1 mole of KOH gives 1 mole of OH⁻ after dissociation, so its n-factor = 1

Normality of KOH, N₂ = Molarity x n-factor = 0.1 x 1 = 0.1

Now, N₁V₁ = N₂V₂

(0.2) (20) = (0.1) (V₂)

V₂ = 40 ml

∴ 40 ml of KOH is required for complete neutralisation.

Hope it helps!!