1
AIEEE 2008
+4
-1
For a reaction $${1 \over 2}A \to 2B$$ rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression
A
$$- {{d[A]} \over {dt}}$$ = $${1 \over 2}{{d[B]} \over {dt}}$$
B
$$- {{d[A]} \over {dt}}$$ = $${1 \over 4}{{d[B]} \over {dt}}$$
C
$$- {{d[A]} \over {dt}}$$ = $${{d[B]} \over {dt}}$$
D
$$- {{d[A]} \over {dt}}$$ = $$4{{d[B]} \over {dt}}$$
2
AIEEE 2007
+4
-1
The energies of activation for forward and reverse reactions for A2 + B2 $$\leftrightharpoons$$ 2AB are 180 kJ mol−1 and 200 kJ mol−1 respectively. The presence of catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol−1. The enthalpy change of the reaction ( A2 + B2 $$\to$$ 2AB) in the presence of catalyst will be (in kJ mol−1)
A
300
B
120
C
200
D
20
3
AIEEE 2007
+4
-1
Consider the reaction, 2A + B $$\to$$ products. When concentration of B alone was doubled, the half-life did not change. When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is
A
L mol-1 s-1
B
no unit
C
mol L-1 s-1
D
s-1
4
AIEEE 2007
+4
-1
A radioactive element gets spilled over the floor of a room. Its half-life period is 30 days. If the initial activity is ten times the permissible value, after how many days will it be safe to enter the room?
A
1000 days
B
300 days
C
10 days
D
100 days
EXAM MAP
Medical
NEET