Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ?

Question

Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ? (A) BeCl2 (B) SrCl2 (C) CaCl2 (D) MgCl2

Tardigrade Admin · Accepted Answer

Metal halide on hydrolysis with water form corresponding hydroxides.
The basic strength of hydroxide increases as we move down in a group. This is because of the increase in size which results in decrease of ionization energy which weakens the strength of

M - O

bonds in

MO H

and thus increases the basic strength.

Amphoteric B e (O H)_{2} Weak base M g (O H)_{2}

C a (O H)_{2} Strong base S r (O H)_{2} B a (O H)_{2}

Hence,

B a (O H)_{2}

will have lowest pH.

Q. Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ?

$B e C l_{2}$

$S r C l_{2}$

$C a C l_{2}$

$M g C l_{2}$

Q. Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ?

BeCl2​

SrCl2​

CaCl2​

MgCl2​

$B e C l_{2}$

$S r C l_{2}$

$C a C l_{2}$

$M g C l_{2}$