NEET-XII-Chemistry
Previous Year Paper year:2017
- #77Which will make basic buffer?
(1) 50 mL of 0.1 M NaOH + 25 mL of 0.1 M ``CH_3COOH``
(2) 100 mL of 0.1 M ``CH_3COOH`` + 100 mL of 0.1 M NaOH
(3) 100 mL of 0.1 M HCl + 200 mL of 0.1 M ``NH_4OH``
(4) 100 mL of 0.1 M HCl + 100 mL of 0.1 M NaOHdigAnsr: 3Ans : ( 3 )
Sol.
(1) + ï‚® +
3 3 2
CH COOH NaOH CH COONa H O
Before 25 mL 50 mL
0
× 0.1M× 0.1 M
= 2.5 mmol = 5 mmol
After 0 2.5 mmol 2.5 mmol
This is basic solution due to NaOH.
This is not basic buffer.
(2) + ï‚® +
= =
3 3 2
CH COOH NaOH CH COONa H O
Before 100 mL 100 mL
0
× 0.1 M × 0.1 M
10 mmol 10mmol
After 0 0 10 mmol
Hydrolysis of salt takes place.
This is not basic buffer.19
(3) + ï‚® +
= =
4 4 2
HCl NH OH NH Cl H O
Before 100 mL 200 mL
0
× 0.1 M × 0.1 M
10 mmol 20 mmol
After 0 10 mmol 10 mmol
This is basic buffer
(4)
+ ï‚® +
= =
2
HCl NaOH NaCl H O
100 mL 100 mLBefore
0
× 0.1 M × 0.1 M
10 mmol 10 mmol
After 0 0 10 mmol
&implies; Neutral solution