Question

A solution of nitric acid is formed by dissolving 5.00grams of nitric acid in enough water to make 1.5 liters of solution.

c. What was the molarity of this solution?

d. What is the pH of this solution?

Answer 1

Molarity = 0.053 M

pH = 1.276

Further explanation

Given

5 g of HNO₃

1.5 L solution

Required

Molarity

pH

Solution

Molarity shows the number of moles of solute in every 1 liter of solution.

mol HNO₃(MW=63 g/mol) :

= mass : MW

= 5 g : 63 g/mol

= 0.079

Molarity :

=0.079 : 1.5 L

= 0.053 M

pH = -log [H⁺]

For strong acids like HNO₃ :

[H⁺] = a.M

a = valence of acid / amount of H⁺ released

M = acid concentration.

HNO₃ ⇒ H⁺ + NO₃⁻⇒ valence 1(amount of H⁺=1)

[H⁺]=1 x 0.053

[H⁺]= 0.053 M

pH= - log 5.3 x 10⁻²

pH = 2 - log 5.3

pH= 1.276