Explain the ‘‘medium of exchange’’ function of money.

The major function of money is medium of exchange and it is its advantage over the barter system of exchange because with money we can buy anything for example if we need to buy gold or vegetable or clothes or house we can buy anything in exchange of money but in barter system the problem of medium of exchange existed.

Suppose I need to buy 10 kg of Wheat and the person having wheat is in need of 10 kg of Rice then I could not exchange or have wheat from him unless and until I have that 10 kg of rice to exchange.