The chemical formula of Ammonia is _____ .
1). NH
2). NH1
3). NH2
4). NH3
1. Two elements which can form a large number of compounds are
2. Which of the following is not a method of estimating national income?
4. Atoms having the same number of protons but different number of neutrons are called :
5. Identify the metal which is nontoxic in nature
6. Water is not effective in extinguishing a fire caused by petrol because
8. Which of the following could be used as fuel in propellant or rockets ?
9. Which of the following substance is highly plastic ?
10. Ozone depletion in the?stratosphere is mainly caused by-