Note: In the following questions match the items of Column I with appropriate item given in Column II.
Match the graph given in Column I with the order of reaction given in Column II. More than one item in Column I may link to the same item of Column II.
Column I Column II
(i)
(ii) (a) first order
(iii) (b) zero order
(iv)
(i)→(a),(ii)→(b),(iii)→(b),(iv)→(a)
(i) →(a),(iv) →(a)
For the first order of a reaction, the rate is directly proportional to the molar concentration of the reactant.
Thus,
Rate=-d[R]/dt=kR⟹-(d[R])/R=kdt
Thus, The above equation gives graph (i) for a first-order reaction.
Integrating both sides from t=0 to t=t at concentration R=R0 to R=R respectively.
We get,
log〖 [R]〗=-kt/2.303+log[R_0]
Where K is the rate constant, R is the molar concentration of the reactant at time t and R0 is the molar concentration of a reactant at time t=0.
Above equation represents the equation of a line i.e. y=mx+c, for y=log [R] and x=t.
Slope is -k/2.303.
Thus, (iv) →(a).
(ii) →(b),(iii) →(b)
For a zero-order reaction, Rate is only depending on rate constant.
Rate=k〖[R]〗^0
Where k is the rate constant and R is the molar concentration of a reactant.
Thus, the rate is constant with respect to the concentration of a reactant. Giving, graph (ii) for a zero-order reaction.
From the above equation, we get,
-(d[R])/dt=k
Integrating both sides from t=0 to t=t at concentration R0 to R respectively. We get,
[R]=-kt+[R_0]
Where R is the molar concentration of a reactant at t=t, R0 is the molar concentration of a reactant at t=0.
The above equation represents the equation of a line i.e. y=mx+c.
Thus, for a concentration vs time graph for a zero-order reaction will be a straight line with slope equals -k.
Thus, the graph (iii) is for a zero-order reaction.