Question

what is difference between lpg and cng gas

Answer 1

Compressed natural gas (CNG) (methane stored at high pressure) is a fuel which can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. ... Its use is also increasing in South America, Europe and North America because of rising gasoline prices.
Liquefied petroleum gas or liquid petroleum gas, also referred to as simply propane or butane, are flammable mixtures of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles

Answer 2

LPG or liquefied petroleum gas is used at home for cooking
CNG or compressed natural gas is used for running of vehicles and also as fuel