Some properties of substances P, Q, R and S are given in the table :

Which of the given substances represents a gaseous non-metal at room temperature ?

Options

A. P
B. R
C. Q
D. S

Answer

B

Explanation

Non-metals are poor conductors of heat and electricity. Substance R represents a gaseous non-metal at room temperature. At `-101^(@)C`, the substance R melts and remains in liquid state below temperature `-35^(@)C`.
At `-35^(@)C`, substance R starts boiling thus, at room temperature `(20-25^(@)C),` it will be a gas. Whereas, substance Q will be in liquid state at room temperature.