MisterBrainly

#17

#a

Group 15 elements have valency 3

• B,Al are the answers

#b

• Oxygen is more reactive

Let's check the EC of both

• Oxygen is smaller in size
• Hence more electronegative.

#c

Decrease in size

• Farther we go in a period more electrons are added to the atom .So nuclear charge increases and atomic radius decreases

#18

#a

• HNO_3

#b

• Nitric acid is a acid so methyl orange turns red

#c

• Used as oxidising agent