Which vs What
Which and What are two kinds of relative pronouns used in the English language with difference. ‘Which’ can be used as a determiner also. In fact it is often used with a noun in a relative clause as in the sentence ‘He may be late in which case we have to wait for him’.
Which and what can both be used with nouns to ask questions as in the sentences
1. Which book has impressed you the most?
2. What musicians do you admire?
In the first sentence you can see that the relative pronoun ‘which’ is used with the noun ‘book’ and in the second sentence you will find that the relative pronoun ‘what’ is used with the noun ‘musicians’ to ask questions. This is one of the main purposes of the usage of the relative pronouns ‘which’ and ‘what’.
Which is used generally in cases wherein there is a limited choice. On the other hand ‘what’ is used when the choice is bigger. This is one of the main differences between the usages of ‘which’ and ‘what’. Observe the two sentences
1. Which color would you like? Green, blue or yellow?
2. What book is your choice?
In the first sentence you can see that the choice given to the person is limited and hence the word ‘which’ is used. On the other hand in the second sentence by the use of the word ‘what’ you can find that the choice offered is certainly bigger.
It is important to know that ‘which’ and ‘what’ can be used as pronouns without nouns for that matter as in the sentences ‘which is better?’ and ‘what is more beautiful between the two? In both the sentences you can see that the noun is not used but is simply substituted by the use of the words ‘which’ and ‘what’ respectively.