KCET2012ChemistryIonic Equilibrium
On adding which of the following, the pH of 20 ~mL of 0.1 ~N HCl will not alter?
Options
- A20 ~mL of distilled water
- B1 ~mL of 0.1 ~N NaOH
- C500 ~mL of HCl of pH =1
- D1 ~mL of 1 ~N HCl
Correct answer
C. 500 ~mL of HCl of pH =1
Step-by-step solution
Milliequivalents of 20 ~mL of 0.1 ~N HCl = N ₁ ~V ₁ =20 0.1=2 (a) pH of distilled water =7 aligned [ H ⁺ ]=10^ - pH =& 10⁻⁷ M milliequivalents &= NV [for HCl , N = M ] &=10⁻⁷ 20=2.0 10⁻⁶ aligned (b) Milliequivalents of NaOH =0.1 1=0.1 (c) pH of HCl =1 [ H ⁺ ]=10⁻¹=0.1 M Milliequivalents =0.1 500=50 (d) Milliequivalents of HCl =1 1=1 Milliequivalents of 500 ~mL of HCl having pH =1 is more than that of 20 ~mL of 0.1 ~N HCl , therefore adding this, pH of 0.1 ~N HCl solution, does not alter.