Question

5. What is the substance responsible for the browning of aut surfaces of vegetables and
fruits called?
a Zinc
b. Melanin
6. Which of the following elements exist as tetratomic molecules?
a. Hydrogen b. Nitrogen
Potassium
Phosphorous
7. What is the chemical formula for sodium oxide?
a. Nao
b. Na o
Nad
a Na .
8. Which gas is released in reaction of vinegar with baking soda?
a. Oxygen
b. Nitrogen c Carbon dioxide Carbon monoxide
9. Which of the following elements exhibits valency 2?
a. Oxygen
b. Sodium
C Aluminium d. Nitragen
​

Answer 1

Answer:

5=b.

6=c.

7=b.

8=ç.

9=c.