The rate Constant of reaction A $\to$ B is 0.6 X 10^-3 mole per second. If the Concentration of A is 5, then the concentration of B after 20 min is:

1. 1.08M

2. 3.60M

3. 0.36M

4. 0.72M

When the initial concentration of a reactant is doubled in a reaction,
its half-life period is not affected. The order of the reaction will be:
1. 0
2. 1
3. 1.5
4. 2 

For the reaction, 
${\mathrm{N}}_2{\mathrm{O}}_5\left(\mathrm{g}\right)\to 2{\mathrm{NO}}_2\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)$
the value of rate of disappearance of N₂O₅ is given as 6.25 x 10^-3mol L^-1s^-1.The rate of formation of NO₂ and O₂ is given respectively as: