An atom has mass number 31 and 16 neutrons. Its atomic number is: MCQ with Answer and Explanation

Explanation:
Boyle's law states that at constant temperature, the volume of a given mass of gas is inversely proportional to pressure: PV = constant. So P ∝ 1/V. Charles' law relates V and T at constant P. Gay-Lussac's law relates P and T at constant V. Boyle's law is used in syringes and scuba diving. Graph of P vs V is a hyperbola; P vs 1/V is a straight line.

Explanation:
Catalytic converters use precious metals like platinum, palladium, and rhodium as catalysts to convert toxic exhaust gases (CO, NOx, unburnt hydrocarbons) into less harmful substances (CO₂, N₂, H₂O) before they are released into the atmosphere. These metals are chosen for their high catalytic activity and durability.

Explanation:
The acidic behavior of HCl is due to the presence of H⁺ (or H₃O⁺) ions, which are generated only when it dissolves in water. Without moisture, HCl doesn't dissociate to produce H⁺, so it doesn't change the color of dry litmus. Both statements are correct and R explains A.