I have read many sentences making use of 'on behalf of' meaning 'as a representative of'. I know behalf is a noun, so when we could use 'on the behalf of' in a sentence? I consulted many websites, but none of them used 'the' article before 'behalf'. Is it wrong to use 'the' before this noun? Why? If i do use it, what would it mean?
on behalf of ,in addition to, on account of etc. are prepostional phrases and they are idiomatic. So we can not use any article before the nouns.
1.I spoke on behalf of my Principal but not on the behalf of
2.Tomorrow is a holiday on account of Diwali.
There are certain phrases such as on fire , send word which do not take any article.