English one word substitution for all competitions exam

Which one is a nucleophilic substitution reaction among the following ?

Which one of the following pairs undergoes Snl substitution reaction faster and why?

Which one of the following reaction is an example of free radical substitution reaction?

Which one of the following pairs undergoes Snl substitution reaction faster and why?

Which of the following compounds will give over all substitution product via. Addition/elimination mechanism with Ethylamine?

When a mutation is limited to the substitution of one nucleotide pair of DNA, it is called as

In an essay competition, the odds in favour of competitors P, Q, R S are 1:2, 1:3, 1:4, and 1:5 respectively. Find the probability that one then win the competitions.

Which one is o, p-directiong group for electrophliic substitution reaction ?