The half life period of a first order chemical reaction is 6.93 minutes. The time required for the completion of 99% of the chemical reaction will be (log 2=0.301)
230.3 minutes
23.03 minutes
46.06 minutes
46.06 minutes
Solid Ba (NO3)2 is gradually dissolved in a 1.0x 10−4 × Na2CO3 solution. At what concentration of Ba2+ will a precipitate begin to form?(Ksp for BaCO3 = 5.1 ×10−9 )
4.1 x 10-5 M
5.1 x 10-5 M
8.1 x 10-8 M
8.1 x 10-8 M
For a reaction 1/2A →2B, rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression
The energies of activation for forward and reverse reactions for A2 + B2 ⇌ 2AB are 180 kJ mol–1 and 200 kJ mol–1 respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol–1. The enthalpy change of the reaction (A2 + B2 → 2AB) in the
presence of catalyst will be (in kJ mol–1) –
300
120
280
280
Consider the reaction, 2A + B → Products. When the concentration of B alone was doubled, the half-life did not change. When the concentration of An alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is –
L mol–1 s–1
no unit
mol L–1s–1
mol L–1s–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 ?
1000 days
300 days
50 days
50 days
Which of the following nuclear reactions will generate an isotope?
neutron particle emission
positron emission
α-particle emission
α-particle emission
A reaction was found to be second order with respect to the concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will
remain unchanged
triple
increase by a factor of 4
increase by a factor of 4
C.
increase by a factor of 4
R∝ [W]2
R'∝ [2CO]2
R∝ 4[W]2
R∝ 4M
In the transformation of , if one emission is an α-particle, what should be the other emission(s)?
Two β–
Two β– and one β+
One β– and one γ
One β– and one γ
In Langmuir’s model of adsorption of a gas on a solid surface
the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
the adsorption at a single site on the surface may involve multiple molecules at the same time
the mass of gas striking a given area of the surface is proportional to the pressure of the gas
the mass of gas striking a given area of the surface is proportional to the pressure of the gas