1

### JEE Main 2019 (Online) 9th January Evening Slot

Consider the following reversible chemical reactions : The relation between K1 and K2 is :
A
K1K2 = ${1 \over 3}$
B
K2 = K13
C
K2 = K1$-$3
D
K1K2 = 3

## Explanation 2

### JEE Main 2019 (Online) 10th January Morning Slot

Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface ?
A B C D ## Explanation

E = W + ${1 \over 2}$mv2

K.E. = hv $-$ 4v0

K.E. = hv + ($-$ hv0)

y = mx + $\underline C$
3

### JEE Main 2019 (Online) 10th January Morning Slot

Consider the given plots for a reaction obeying Arrhenius equation (0oC < T < 300oC) : (K and Ea are rate constant and activation energy, respectively) Choose the correct option :
A
I is right but II is wrong
B
Both I and II are correct
C
Both I and II are wrong
D
I is wrong but II is right

## Explanation

Arrhenius Equation -

Arrhenius gave the quantitative dependence of rate constant on temperature by the Arrhenius equation.

- wherein

$k = A{e^{ - {E_a}/RT}}$

${\mathop{\rm lnk}\nolimits} = lnA - {{{E_a}} \over {RT}}$

k = Rate constant

as we have learned in Arrhenius equation when we increase Ea, K should decrease As T increases, power of exponential increases so k also increase.

Hence, both the plots are correct.
4

### JEE Main 2019 (Online) 10th January Evening Slot

For an elementary chemical reaction, the expression for ${{d\left[ A \right]} \over {dt}}$ is
A
2K1[A2] – K –1 [A]2
B
K1[A2] – K –1 [A]2
C
K1[A2] + K –1 [A]2
D
2K1[A2] – 2K –1 [A]2

## Explanation 