NEET Solved Paper 2014 Question 6
Question: Which of the following salts will give highest pH in water? [AIPMT 2014]
Options:
A) $ KCl $
B) $ NaCl $
C) $ Na _2CO _3 $
D) $ CuSO _4 $
Show Answer
Answer:
Correct Answer: C
Solution:
The highest pH refers to the basic solution containing $ O{H^{-}} $ ions.
Therefore, the basic salt releasing $ O{H^{-}} $ ions on hydrolysis will give highest pH in water.
Only the salt of strong base and weak acid would release $ O{H^{-}} $ ion on hydrolysis.
Among the given sate, $ Na _2CO _3 $ corresponds to the basic salt as it is formed by the neutralisation of $ NaOH $ [strong base] and $ H _2CO _3 $ [weak acid].
$ CO_3^{2-}+H _2O\rightarrow HCO_3^{-}+O{H^{-}} $
