Exercise 2

Question 11 :

The first metal used by man was


A). iron
B). copper
C). gold
D). bronze
Answer : Option B

Question 12 :

The most electropositive elements among the following is


A). Na
B). Ca
C). K
D). Cs
Answer : Option D

Question 13 :

The method that cannot be used for removing permanent hardness of water is


A). adding sodium carbonate
B). distillation
C). adding caustic soda
D). boiling
Answer : Option D

Question 14 :

The following are the half lives of four active isotopes. Which one of the following is the most dangerous to handle?


A). 3 billion years
B). 100 years
C). 0.01 minute
D). 13 days
Answer : Option C

Question 15 :

The gas used for artificial ripening of green fruit is


A). ethylene
B). ethane
C). carbon dioxide
D). acetylene
Answer : Option A