Class 12th

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Correct Option: (iii)

 The difference between electrode potential potentials of two electrodes when no current is drawn through the cell is termed as cell emf. It is the energy provided by a cell per coulomb of charge passing through it. It is the maximum potential difference between the electrodes of a cell.

This is a Short Answer Type Question as classified in NCERT Exemplar

At room temperature, the redox titration of  KMnO₄vs oxalic acid is exceedingly slow; nevertheless, as the temperature rises, so does the rate of reaction. At a temperature of 500c., KMnO₄ is acidified with dil H₂SO₄ and interacts with oxalic acid.

This is a Short Answer Type Question as classified in NCERT Exemplar

Thermodynamic feasibility is determined by ΔG factors. So, while the conversion of diamond to graphite is thermodynamically viable, the reaction is sluggish and has a high activation energy.

Gibb's free energy is ΔG
ΔG =Rtlnk

ΔG_{P, T $>$}  o

at constant pressure and temperature should be negative or less than 0.

For example, Diamond to be converted to Graphite

ΔG=−ve

It is theoretically conceivable, but the rate is extremely slow, and the activation energy is extremely high. The energy required to transform diamond to graphite is insufficient.

This is a Multiple Choice Questions as classified in NCERT Exemplar

This is a Short Answer Type Question as classified in NCERT Exemplar

The pace of any reaction is determined by the concentration of the reactants, the rate of any reaction generally declines during the reaction. As the reaction progresses, the reactant concentration declines, and the product concentration rises.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Acetic acid is a weak electrolyte and the number of ions on dilution increases due to an increase in the degree of dissociation. In the case of strong electrolytes the number of ions remains the same but interionic attraction decreases.

Xenon form compounds due to the high electronegativity of fluorine and oxygen, low ionization energy compared to lighter noble gases, and the availability of empty d-orbitals. This breaks the old assumption about noble gases being entirely inert.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: The cell reaction of a lead storage battery is as follows;

Pb + PbO₂ + 2H₂SO₄→2H₂SO₄ + 2H₂O

The density of electrolytes changes because water is formed and sulphuric acid is consumed as a product during discharge of the battery