Question

1. Organize the following acids form strongest to weakest. aqua acid among these three: [Fe(H2O)6]3+, [Zn(H2O)6]2+ and [Mg(H2O)6]2+. Explain you answer.

2. If you replace one -OH group in H2SO4 with –CCl3,
a. the resulting acid, H(CCl3)SO3 is weaker than H2SO4.
b. the resulting acid, H(CCl3)SO3 is stronger than H2SO4
c. we cannot say anything about the acidity of the new compound relative to H2SO4.

3. Consider a solvent AB that undergoes autoionization to produce AB2– and A+ ions. Then the correct definition of acids and bases in this solvent would be:
a. An acid would increase the concentration of A+ while a base would increase the concentration of AB2–.
b. An acid would increase the concentration of AB2– while a base would increase the concentration of A+.
c. The definition cannot be provided without knowing the exact nature of A and B.

Answer 1

Answer 1

The acidic nature of aqua acids depends on :

• Charge of metal ion : More is the charge on metal, more it will attract the electrons and more will be acidity.

• Radius of metal cation: For same charges, smaller is the radius more will be the acidity.

Now, Fe3+ has highest charge while out of Mg2+ and Zn2+, the radius is more for Zn2+.

So, correct order is [Zn(H2O)6]2+ > [Mg(H2O)6]2+ > [Fe(H2O)6]3+.

Answer 2

CCl3 group is electron withdrawing group. It will tend to stabilize the deprotonated acid more than OH does in H2SO4. So, the acidic nature increases.

Correct answer is b)

Answer 3

An acid is something that increases cationic part of the solvent.

So, correct answer is a)