Formula For Salts of Strong Acids and Weak Bases

Sep 06, 2022, 16:45 IST

Salts of strong acids and weak bases [SA-SB]

Such salts give acidic solutions in water. Some of such salts are : NH4Cl, ZnCl2, FeCl3 etc. For the purpose of discussion, we will consider hydrolysis of NH4Cl. For More Chemistry Formulas just check out main pahe of Chemsitry Formulas. 

When NH4 Cl is put in water, it completely ionises in water to give NH4+ and Cl- ions. NH4+ ions combine with OH- ions furnished by weakly dissociated water to form NH4OH (weak base). Now for keeping Kw constant, water further ionises to give H+ and OH- ions, where OH- ions are consumed by NH4+ ions leaving behind H+ ions in solution to give an acidic solution. 

salts of strong acids

pH of solution :

ph of solution

Example For Salts of Strong Acids and Weak Bases

Example 1                  

The basic ionisation constant for hydrazine, N2H4 is 9.6× 10–7. What would be the percent hydrolysis of 0.1 N2H5Cl ?

A. 0.016
B. 3.2
C. 1.6
D. 0.032

Ans. D

Example 2      

The pH of a 0.02 M aqueous solution of NH4Cl  is equal to

A. 3.78
B. 4.73
C. 5.48
D. 7.00

Ans. A

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