1. Brass gets discoloured in air because of the presence of which of the following gases in air?
B. Hydrogen sulphide
C. Carbon dioxide
2. Which of the following is a non metal that remains liquid at room temperature?
3. Chlorophyll is a naturally occurring chelate compound in which central metal is
4. Which of the following is used in pencils?
5. Which of the following metals forms an amalgam with other metals?
6. Chemical formula for water is
7. The gas usually filled in the electric bulb is
C. carbon dioxide
8. Washing soda is the common name for
A. Sodium carbonate
B. Calcium bicarbonate
C. Sodium bicarbonate
D. Calcium carbonate
9. Quartz crystals normally used in quartz clocks etc. is chemically
A. silicon dioxide
B. germanium oxide
C. a mixture of germanium oxide and silicon dioxide
D. sodium silicate
10. Which of the gas is not known as green house gas?