The rubbing surface of a matchbox has powdered glass and a little red ________________.
1). antimony
2). arsenic
3). silicon
4). phosphorus
1. The major harmful gas emitted by automobile vehicles which causes air pollution is
2. German silver an alloy does not contain the metal
4. Who was the first man to go to space?
6. Cement is usually a mixture of
7. A powerful eye irritant present in smog is
8. Brown stains in vessels and clothes indicate the presence of high quantities of ________ in water
9. Which of the following is chiefly present in LPG (Liquefied Petroleum Gas)?