Question

Which one below is a pseudohalide?
A. $CN$
B. $ICl$
C. $I{F_3}$
D. ${I_3}$

Answer 1

Hint - We will start by defining the pseudohalide to first make it clear about it and after that we will discuss the difference between pseudohalide and a halogen then with the help of this difference we will find our answer.

Complete answer:

A pseudohalide is an anion which has similar properties to a halogen, but not a real halogen. True halogens are those which belong to the Group 17 of the periodic table.

 The pseudohalide is an anionic compound with stable structure and can be used as general substitutes in reaction with similar mechanisms.

They resemble some of the properties of halides such as being weak bases by themselves that form strong acids when protonated, form neutral salts when combined with metals and oxidizes electropositive elements.

However, it is not very easy to identify a pseudohalide as they are not always identical. But we can identify them by taking a look at their molecular formula as pseudohalide ions consist of two or more electronegative atoms at least one of which is nitrogen.
And also the key difference between halogens and pseudohalide is that the halogens are group 17 elements whereas the pseudohalides are combinations of different elements.

So, after comparing all the options with these characteristics we say that $ICl$, $I{F_3}$ and ${I_3}$ are not pseudohalides.
Therefore, option A is the right answer.

Note – Pseudohalide is a related term of pseudohalogen. Pseudohalogens are polyatomic analogues of halogens, or also called ‘fake’ halogens, whose properties resemble that of true halogens. These kinds of questions can be done with eliminating processes, i.e., eliminating the wrong options to get the right option, but for that all the properties must be remembered.