What will come in place of question mark(?) in the following number series?

BJ , CL , EN , HP , ? 

Arrange the following words in the order of the dictionary-
1. Chemistry
2. Chamber
3. Cheap
4. Cheerful

How many pair of letters are there in the word “EFFECTIVE” which has as many letters (in both forward and backward direction) in between as they have in English alphabet series?

Find the missing (?) in the series AIQ, BJR, CKS, DLT, ?, 

Find the next term in the given series.
B2, K12, T72, ______

Which letter will come in place of the question mark (?) in the following series?
FLO, H?Q, JPS, LRU

In each of the following questions, find the missing letters in the given letters.
AMV ,   FQX, KUZ , _?_

Complete the following alphabet series.
SQO, USQ, WUS, ?