A radioactive element gets spilled over the floor of a room. Its half-life period is 30 days. If the initial activity is ten times the permissible value, after how many days will it be safe to enter the room ?

• 1000 days

• 300 days

• 50 days

• 100 days

D.

100 days

A reaction involving two different reactants can never be

• Unimolecular reaction

• First order reaction

• second order reaction

• Bimolecular reaction

A reaction was found to be second order with respect to the concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will

• remain unchanged

• triple

• increase by a factor of 4

• double

A schematic plot of In K_eq versus inverse of temperature for a reaction is shown below



The reaction must be

• exothermic

• endothermic

• one with negligible enthalpy change temperature

• highly spontaneous at ordinary

A.

exothermic

An amount of solid NH₄HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm. Pressure. Ammonium hydrogen sulphide decomposes to yield NH₃ and H₂S gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm. The equilibrium constant for NH₄HS decomposition at this temperature is

• 0.30

• 0.18

• 0.17

• 0.11

D.

0.11