Which type of fumes are evolved when copper is added to acidified nitrates?

1. NO₂ fumes
2. N₂O fumes
3. N₂ fumes
4. N₂O₃ fumes

The molecular mass of CO₂ and O₂ are approximately 44 and 32 respectively. Which of the following statements regarding the mass of oxygen and number of molecules of oxygen is correct?

P. The mass of oxygen in 2.24 litres of CO₂ is 3.2 g

Q. The number of molecules of oxygen present in it is 6.022 x 10²³

1. Only P
2. Only Q
3. Both P and Q
4. Neither P nor Q

Magnalium is an alloy of

1. aluminium and magnesium
2. aluminium and copper
3. iron
4. copper

An element X belongs to group II A and another element Y belongs to group V A of the periodic table. Which of the following could be correct?

P. Valency of Y will be 5.

Q. Element X will have 2 valence electrons.

R. Element X belongs to group number 2

1. Only P
2. Q
3. R
4. Both Q and R