2. Which is laughing gas?
3. Which of the following is used in pencils?
4. Most soluble in water is:
5. Which of the following is an element?
6. Which one of the following is the best conductor of electricity?
7. Bio gas contains mainly:
9. Balloons are filled with:
10. Which metal is used in storage batteries?
11. Which form of phosphorous is used in safety matches?
12. Which of the following is the lightest metal?
13. Diamond is an allotropic form of:
14. Water has maximum density at:
15. The element present in the largest amount in rocks and minerals is:
16. The most malleable metal is:
17. Which one of these is used in beauty parlours for hair setting?
18. From which mineral is radium obtained?
19. The gas used to extinguish fire is: