Question

calculate pH of 1.52 g nitric acid in 575 ml of solution​

Answer 1

Given:

Mass of nitric acid = 1.52g

Volume of solution = 575ml

To find:

pH of the solution

Solution:

In nitric acid solution, solvent is water.

The chemical reaction involved is-

  HNO₃ +  H₂O  →  NO₃⁻  +   H₃O⁺

Firstly, find the concentration of solution i.e. find the molarity of the solution,

Molarity is number of moles of solute dissolved in 1 liter of solution.

To calculate molarity formula used is -

         $Molarity = \frac{n}{V(L)}$

or,          $Molarity = \frac{n}{V(ml)} \times 1000$

here, n = number of moles

         V = volume of solution(ml)

To find number of moles, we have

         $n = \frac{w}{MM}$

here, n = number of moles

        w = given mass

         MM = molecular mass

Molecular mass of nitric acid(HNO₃) = 63gmol⁻¹

So,       $n = \frac{1.52g}{63gmol^-^1}$

          n = 0.024 mol

therefore,   $Molarity = \frac{0.024}{575} \times 1000$

                 Molarity = 0.042M

Molarity of HNO₃ solution = 0.042M

therefore, Concentration of H⁺ ions = 0.042M

so,

Formula used to find pH is -

        pH = -log[H⁺]

         pH = - log0.042

         pH = - (-1.4)

         pH = 1.4

So, the pH of the solution is 1.4.