JEE Main201910 Apr 2019Morning ShiftChemistryIonic EquilibriumActual
Consider the following statements ( a ) The pH of a mixture containing 400 m L of 0.1 M H 2 S O 4 and 400 m L of 0.1 M N a O H will be approximately 1.3 . ( b ) Ionic product of water is temperature dependent. ( c ) A monobasic acid with K a = 10 - 5 has a p H = 5 . The degree of dissociation of this acid is 50 % . ( d ) The Le Chatelier's principle is not applicable to common-ion effect. The correct statements a
Options
- A( b ) and ( c )
- B( a ) , ( b ) and ( d )
- C( a ) and ( b )
- D( a ) , ( b ) and ( c )
Correct answer
D. ( a ) , ( b ) and ( c )
Step-by-step solution
Strong acid + Strong base mixture n H 2 S O 4 > n [ N a O H ] So H + will be more H + = 2 × 0.1 × 400 - 0.1 × 400 800 = 0.05 p H = - log H + = - log 0.05 = 1.3 (b) The ionic product of water is temperature dependent (c) H C O O H ⇌ H + + H C O O - (weak acid) k a = C α 2 1 - α k a = C α . α 1 - α k a = H + α 1 - α 10 - 5 = 10 - 5 × α 1 - α 1 - α = α α = 1 2 = 0.5 (d) Le-Chatelier’s Principle in applicable on Common Ion Effect