RATE OF REACTION-CHEMICAL EQUILIBRIUM-IV : NUMERICALS

SOLVED NUMERICALS OF TEXT BOOK (GSEB)

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1. If 49 grams of H₂SO₄ is dissolved in 5 litres of aqueous solution, what will be the molarity of the solution ?
   
   SOLUTION :
   

   
   mass of H₂SO₄ in grams
   Mole of H₂SO₄ =    --------------------------------
   molecular mass of H₂SO₄

   
   

   =    49/98
   = 0.5 mole

   
   

   
   Mole of H₂SO₄               
   Molarity of H₂SO₄    =   -----------------               
   Volume in litres               
   =0.5 mole/5 litre = 0.1 mole litre^-1 = 0.1 M

   
   
2. Calculate the p^H of 0.02 M aqueous solution of HCl.
   
   SOLUTIONAs HCl is a strong acid it ionises completely.
   ∴ Concentration of HCl = Concentration of H₃O⁺
   
   HCl_(aq) + H₂O_(l) → H₃O⁺_(aq) + Cl^-_(aq)
   
   (0.02 M)           (0.02 M)
   
   Now, p^H = -log₁₀[H₃O⁺]
   
               = -log₁₀[0.02]
   
               = -log₁₀[2 x 10^-2]
   
               = -[0.3010 - 2.0000]
   
               = 2.0000 - 0.3010
   
               = 1.6990 _________[ANS]
   
   
3. 9.8 gram H₂SO₄ is dissolved in 5 litre of aqueous solution. Find the p^H of the solution.
   
   SOLUTION
   
   
   
4. If the p^H of an aqueous solution is changed from 5 to 4, how many times will be the change in the concentration of H₃O⁺ ion ?
   
   SOLUTION
   
   
   
5. Calculate the p^H and p^OH of 0.03 M aqueous solution of NaOH.
   
   SOLUTION