Question

which of the following molecules is known for having a triple bond?
carbon dioxide
oxygen
nitrogen
hydrogen

which metal(s) can displace hydrogen?
lead
copper
platinum
iron
two of them

Explanation:

First Question:

• Carbon dioxide (\(CO_2\)) has double bonds (\(O = C = O\)).
• Oxygen (\(O_2\)) has a double bond (\(O = O\)).
• Nitrogen (\(N_2\)) has a triple bond (\(N \equiv N\)) as each N atom contributes 3 electrons for bonding to achieve an octet.
• Hydrogen (\(H_2\)) has a single bond (\(H - H\)).

Second Question:

• Metals more reactive than hydrogen (based on activity series) can displace \(H\) from acids.
• Lead (Pb) and Iron (Fe) are more reactive than \(H\) (Pb is above \(H\) in some activity series interpretations for dilute acids, Fe is clearly above \(H\)).
• Copper (Cu) and Platinum (Pt) are less reactive than \(H\) and cannot displace it. So lead and iron (two metals) can displace \(H\), hence "two of them" is correct.

Answer:

C. nitrogen