JEE Advanced (Fill in the Blanks): Chemical Kinetics & Nuclear Chemistry

Fill in the Blanks

1. An element   undergoes an α-emission followed by two successive β-emissions. The element formed is ............. .           (1982 - 1 Mark)

Ans:   

Solutions : 
 TIPS/Formulae :
When an element emits α -particle atomic mass decreases by four and atomic number decreases by two. Loss of β - particle results in increase in atomic number by 1 and no
change in atomic mass.

2. The rate of chemical change is directly proportional to ............... . (1985 - 1 Mark)

Ans:  Product of active masses of reactants at that temperature

Solutions : 
 Product of active masses of reactants at that time

3. The number of neutrons in the parent nucleus which gives  on beta emission is ............... . (1985 - 1 Mark)

Ans:  8

Solutions :  

4. The hydrolysis of ethyl acetate in ............... medium is a ............... order reaction. (1986 - 1 Mark)

Ans:  acidic, first (or basic, second)

5. A radioactive nucleus decays emitting one alpha and two beta particles; the daughter nucleus is ............... of the parent. (1989 - 1 Mark)

Ans:   isotope

Solutions :  Isotope; (because new atom has same atomic number but different atomic mass).

6. For the reaction N2 (g) + 3H₂ (g) → 2NH₃ (g), under certain conditions of temperature and partial pressure of the reactants, the rate of formation of NH³ is 0.001 kg h^-1. The rate of conversion of H₂ under the same condition is........kg h^-1.

Ans:  1.765 × 10^-4 kg/hr

Solutions : N₂(g) + 3H₂(g) -→ 2NH₃(g)
Here Rate of reaction = 1/3 [Rate of disappearance of H₂] = 1/2 [Rate of appearance of NH₃]
  

 = 1.765 × 10^-4 kg/hr.

7. In the Arrhenius equation,  A may be termed as the rate constant at .............. . (1997 - 1 Mark)

Ans:   very high temperature or zero activation energy

Solutions : very high temperature (T=∞) or zero activation energy