1
JEE Main 2021 (Online) 31st August Morning Shift
Numerical
+4
-1
For a first order reaction, the ratio of the time for 75% completion of a reaction to the time for 50% completion is ____________. (Integer answer)
2
JEE Main 2021 (Online) 31st August Morning Shift
Numerical
+4
-1
According to the following figure, the magnitude of the enthalpy change of the reaction

A + B $$\to$$ M + N in kJ mol$$-$$ is equal to ___________. (Integer answer)

3
JEE Main 2021 (Online) 27th August Evening Shift
Numerical
+4
-1
The first order rate constant for the decomposition of CaCO3 at 700 K is 6.36 $$\times$$ 10$$-$$3s$$-$$1 and activation energy is 209 kJ mol$$-$$1. Its rate constant (in s$$-$$1) at 600 K is x $$\times$$ 10$$-$$6. The value of x is ___________. (Nearest integer)

[Given R = 8.31 J K$$-$$ mol$$-$$1; log 6.36 $$\times$$ 10$$-$$3 = $$-$$2.19, 10$$-$$4.79 = 1.62 $$\times$$ 10$$-$$5]
4
JEE Main 2021 (Online) 27th August Morning Shift
Numerical
+4
-1
The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is

$$2{K_2}C{r_2}{O_7} + 8{H_2}S{O_4} + 3{C_2}{H_6}O \to 2C{r_2}{(S{O_4})_3} + 3{C_2}{H_4}{O_2} + 2{K_2}S{O_4} + 11{H_2}O$$

If the rate of appearance of Cr2(SO4)3 is 2.67 mol min$$-$$1 at a particular time, the rate of disappearance of C2H6O at the same time is _____________ mol min$$-$$1. (Nearest integer)