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What advantage do the fuel cells have over primary and secondary batteries?
Concept: Fuel Cells
Which of the following solutions of KCl will have the highest value of molar conductivity?
Concept: Conductance of Electrolytic Solutions >> Variation of Conductivity and Molar Conductivity with Concentration
Give reasons:
Mercury cell delivers a constant potential during its life time.
Concept: Batteries >> Primary Batteries
The rate constant of a first order reaction increases from 2 × 10−2 to 4 × 10−2 when the temperature changes from 300 K to 310 K. Calculate the energy of activation (Ea).
(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
Concept: Temperature Dependence of the Rate of a Reaction
The rate of a reaction quadruples when the temperature changes from 293 K to 313 K. Calculate the energy of activation of the reaction assuming that it does not change with temperature.
Concept: Temperature Dependence of the Rate of a Reaction
For a reaction R ---> P, half-life (t1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction?
Concept: Factors Influencing Rate of a Reaction
Define the following term:
Pseudo first-order reaction
Concept: Factors Influencing Rate of a Reaction
For a reaction
\[\ce{2H2O2->[I^-][Alkaline medium]2H2O + O2}\]
The Proposed mechanism is given below:
(1) H2O2+I- → H2O+IO-(slow)
(2) H2O2+IO-→H2O+I-+O2(fast)
(i) Write the rate law for the reaction.
(ii) Write the overall order of a reaction.
(iii) Out of steps(1) and (2), which one is the rate-determining step?
Concept: Effect of Catalyst on the Rate of Reaction
The decomposition of NH3 on a platinum surface is a zero-order reaction. If the rate constant (k) is 4 x 10-3 ms-1, how long will it take to reduce the initial concentration of NH3 from 0.1 M to 0.064 M?
Concept: Zero Order Reactions
What are interstitial compounds?
Concept: General Properties of the Transition Elements (D-block)
Define lanthanoid contraction.
Concept: F-block Elements >> The Lanthanoids
Account for the following :
Zr and Hf have almost similar atomic radii.
Concept: F-block Elements >> The Lanthanoids
Complete the following equations : 2 MnO2 + 4 KOH + O2 →
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Complete the following equations : 2 Na2CrO4 + 2 H + →
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
Concept: General Properties of the Transition Elements (D-block)
Why do actinoids show a wide range of oxidation states?
Concept: F-block Elements >> The Actinoids
Write on similarity between the chemistry of lanthanoids and actinoids.
Concept: F-block Elements >> The Actinoids
Explain effects of lanthanoid contraction.
Concept: F-block Elements >> The Lanthanoids
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Arrange the following in the order of the property indicated against each set :
HF, HCl, HBr, HI − increasing bond-dissociation enthalpy.
Concept: "D" and "F" Block Elements Numericals
