Question

$$Al{F_3}$$  is soluble in $$HF$$  only in presence of $$KF.$$ 
It is due to the formation of

A. $${K_3}\left[ {Al{F_3}{H_3}} \right]$$
B. $${K_3}\left[ {Al{F_6}} \right]$$  
C. $$Al{H_3}$$
D. $$K\left[ {Al{F_3}H} \right]$$
Answer :   $${K_3}\left[ {Al{F_6}} \right]$$
Solution :
Key Idea $$A{l^{3 + }}$$ shows maximum coordination number 6, thus it will form $$AlF_6^{3 - }.$$
$${Al{F_3}}$$  forms $${K_3}\left[ {Al{F_6}} \right]$$   when dissolved in $$HF$$  in the presence of $$KF$$  as shown below :
\[Al{{F}_{3}}+3KF\xrightarrow{HF}{{K}_{3}}\left[ Al{{F}_{6}} \right]\]

Releted MCQ Question on
Inorganic Chemistry >> P - Block Elements

Releted Question 1

The reddish brown coloured gas formed when nitric oxide is oxidised by air is

A. $${N_2}{O_5}$$
B. $${N_2}{O_4}$$
C. $$N{O_2}$$
D. $${N_2}{O_3}$$
Releted Question 2

The temporary hardness of water due to calcium carbonate can be removed by adding —

A. $$CaC{O_3}$$
B. $$Ca{\left( {OH} \right)_2}\,$$
C. $$CaC{l_2}$$
D. $$\,HCl$$
Releted Question 3

Which of the following is most stable to heat

A. $$HCl$$
B. $$HOCl$$
C. $$HBr$$
D. $$HI$$
Releted Question 4

White $$P$$ reacts with caustic soda. The products are $$P{H_3}$$ and $$Na{H_2}P{O_2}.$$   This reaction is an example of

A. Oxidation
B. Reduction
C. oxidation and reduction
D. Neutralisation

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P - Block Elements


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