Question

Order of Covalent bond:
A. $KF > KI ; LiF > KF$ 
B. $KF < KI ; LiF > KF$ 
C. $SnCl _4> SnCl _2 ; CuCl > NaCl$ 
D. $LiF > KF ; CuCl <NaCl$
E. $KF < KI ; CuCl > NaCl$ 
Choose the correct answer from the options given below:

• A. A, B only
• B. B, C only
• C. B, C, E only
• D. C, E only

Answer 1

The Correct Option is C

The order of covalent character can be predicted using Fajans' Rule, which states: 

1. Covalent character increases with smaller cation size and larger anion size. 

2. Covalent character increases with higher charge on the cation. 
Now, analyze each statement: A: KF \(> \text{KI}; \, \text{LiF} > \text{KF}\): 

False. KF has less covalent character than KI because the larger iodide ion polarizes the cation more effectively. 
B: KF \(< \text{KI}; \, \text{LiF} > \text{KF}\): 

True. KI is more covalent than KF, and LiF is less ionic than KF due to the smaller size of \( \text{Li}^+ \). 
C: SnCl\(_2 > \text{SnCl}_4; \, \text{CuCl} > \text{NaCl}\): 

True. SnCl\(_2\) is more covalent than SnCl\(_4\) because Sn\(^2+\) is more polarizing. CuCl is more covalent than NaCl because \( \text{Cu}^+ \) is smaller and has higher polarizing power than \( \text{Na}^+ \). 
D: \(\text{LiF} > \text{KF}; \, \text{CuCl} < \text{NaCl}\): 

False. CuCl is more covalent than NaCl. 
E: KF \(< \text{KI}; \, \text{CuCl} > \text{NaCl}\): 

True. KF is less covalent than KI, and CuCl is more covalent than NaCl. 
Thus, the correct choices are B, C, and E.