Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions

A cubic solid is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound? What are the coordination numbers of P and Q?

Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.

Aluminium crystallises in a cubic close-packed structure. Its metallic radius is 125 pm.

1. What is the length of the side of the unit cell?
2. How many unit cells are there in 1.00 cm³ of aluminium?

The cell in which the following reactions occurs: \[\ce{2Fe^{3+}_{( aq)} + 2I^-_{( aq)} -> 2Fe^{2+}_{( aq)} + I2_{(s)}}\] has \[\ce{E^Θ_{cell}}\] = 0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.

What will be the effect of temperature on rate constant?

The rate of the chemical reaction doubles for an increase of 10 K in absolute temperature from 298 K. Calculate E_a.

The activation energy for the reaction \[\ce{2 HI_{(g)} -> H2_{(g)} + I2_{(g)}}\] is 209.5 kJ mol⁻¹ at 581K. Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy?

The rate constant for the decomposition of N₂O₅ at various temperatures is given below:

Draw a graph between ln k and `1/T` and calculate the values of A and E_a. Predict the rate constant at 30º and 50ºC.

The rate constant for the decomposition of hydrocarbons is 2.418 × 10⁻⁵ s⁻¹ at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor?

Consider a certain reaction \[\ce{A -> Products}\] with k = 2.0 × 10⁻² s⁻¹. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L⁻¹.

The decomposition of hydrocarbon follows the equation k = `(4.5 xx 10^11 s^-1) e^(-28000 K//T)`

Calculate E_a.

The decomposition of A into product has value of k as 4.5 × 10³ s⁻¹ at 10°C and energy of activation 60 kJ mol⁻¹. At what temperature would k be 1.5 × 10⁴ s⁻¹?

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.

What role does adsorption play in heterogeneous catalysis?

Give four examples of heterogeneous catalysis.

Out of C and CO, which is a better reducing agent at 673 K?

Giving examples, differentiate between ‘roasting’ and ‘calcination’.

Why copper matte is put in silica lined converter?

Out of C and CO, which is a better reducing agent for ZnO?

Which is the last element in the series of the actinoids? Write the electronic configuration of this element. Comment on the possible oxidation state of this element.