'IT' must always follow a noun, not an action
eg: Frank says i took his cookies, but i didn't do it --> wrong
Frank says i took his cookies, btu i didn't take them. --> right

Same mistake in posting:
https://www.beatthegmat.com/viewtopic.php?t=2395

R

711. The Commerce Department announced that the economy grew during the second quarter at a 7.5 percent annual rate, while inflation eased when it might have been expected for it to rise.
(A) it might have been expected for it to rise
(B) it might have been expected to rise
(C) it might have been expected that it should rise
(D) its rise might have been expected
(E) there might have been an expectation it would rise

A is clearly wrong...the use of the word "it" twice makes it redundant and wordy..

C suffers from the same problem
D uses passive voice unnecessarily
Between B & E, B is crisp and precise

what does 'IT' refer to in B?

it might have been expected to rise = people expected it (inflation) to rise

According to me, "it" in option B refers to inflation.

The other thing not clear is the usage of "have".

BTG Experts - Please clarify , what does "it" refer to and why there is "have" in option B

The same pronoun used twice in a sentence needs to have the same antecedent.

In choice (A), "it might have been expected for it to rise" - the two "it" refer to different antecedents (in fact the first 'it' is used as a placeholder and has no antecedent), and hence the answer choice is incorrect.