Question

Excess FeCl3 is hydrolysed with water forms a colloidal sol representated as
(A) Fe2O3. xH2O/Fet3
(B) Fe2O3.2H2O/OH
(C) FeCl3 Fe+3
(D) FeCl3/C1
​

Answer 1

Answer:

no

Explanation:

When FeCl

3

sol is treated with hot water, it forms Fe(OH)

3

forming Fe

3+

ions(in excess amount) and these positive ions are adsorbed preferentially. Further, when NaOH is mixed, again there is formation of Fe(OH)

3

but now OH

−

ions are in excess . Therefore, they will get preferentially adsorb and form negatively charged colloid.

Answer 2

Excess FeCl₃ is hydrolyzed with water forms a colloidal sol represented as (A) Fe₂O₃.xH₂O/Fe³⁺

Explanation:

• When ferric chloride is added to boiled water, there is formation of ferric oxide which instantaneously reacts with Fe³⁺ ions to produce sol of hydrated ferric oxide (positively charged).
• When it reacts with sodium hydroxide, the negatively charged sol with OH⁻ ions are formed.
• Fe₂O₃.xH₂O/Fe³⁺ + NaOH → Fe₂O₃.xH₂O/OH⁻