Which of the following mixtures can act as buffer?

Options

A. `H_2CO_3+ NaOH (1.5 : 1` molar ratio)
B. `H_2CO_3+NaOH (1.5 : 2 `molar ratio)
C. `NH_4OH + HCl (5 : 4` molar ratio)
D. ` NH_4OH +HCl (4: 5` molar ratio)

Answer

A, B, C

Explanation

` {:( H_2CO_3 +, NaOH , to NaHCO_3+H_2O ) ,(1.5M , 1M, 0),(1.0, -, 1M),( 0.5M,, ):}`
guffer is formed
(b) ` {:( H_2CO_3 + , NaOH to , NaHCO_3+H_2) , ( 1.5M , 2M, 0),( -, 1.5M , 1.5 M),( , 0.5 M , ):}`
` {:( NaHCO_3+ , NaOH to , Na_2CO_3+H_2O ),( 1.5 M, 0.5 M , 0 ),( 0.5 M ,- , 0.5 M),( 1.0 M,, ) :}`
buffer is formed
( c) ` {:( NH_4 OH +, HCl to, NH_4Cl + H_2O ),( 5M, 4M, 0),(4M, -, 4M),( 1M,, ):}`
(d) acid is excess