The treatment of galena with HNO₃ produces a gas that is

The correct options are paramagnetic and colorless.

Step 1: Understand the reaction of galena with nitric acid

Galena is lead(II) sulfide, having the chemical formula $\mathrm{PbS}$. When galena is treated with dilute nitric acid (${\mathrm{HNO}}_3$), it undergoes an oxidation-reduction reaction to produce lead(II) nitrate, sulfur, nitric oxide ($\mathrm{NO}$) gas, and water.

The balanced chemical equation for the reaction is:

$3\mathrm{PbS}+8{\mathrm{HNO}}_3\to 3\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2+3S+2\mathrm{NO}+4H_{2}O$

Thus, the gas produced during this reaction is nitric oxide ($\mathrm{NO}$).

Step 2: Analyze the properties of Nitric Oxide ($\mathrm{NO}$) gas

1. Color: Nitric oxide ($\mathrm{NO}$) is a colorless gas in its gaseous state.

2. Magnetic Property: The total number of valence electrons in $\mathrm{NO}$ is 5 (from Nitrogen) + 6 (from Oxygen) = 11 electrons. Because it contains an odd number of electrons, it has one unpaired electron. Molecules with unpaired electrons display paramagnetic behavior. Therefore, $\mathrm{NO}$ gas is paramagnetic.

3. Geometry: Being a diatomic molecule, its geometry is linear, not bent.

4. Acid-Base Nature: $\mathrm{NO}$ is a neutral oxide, not an acidic oxide.

Conclusion:

The gas produced is $\mathrm{NO}$, which is both paramagnetic and colorless.