Chemistry

Due to their high electronegativity, small atomic size, greater ability to form multiple bonds, and absence of d-orbitals, the first elements of each group behave differently.

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

Ans: Standard hydrogen electrode (SHE) is used as a reference electrode and its electrode potential is assumed to be zero. The electrode potential of other electrodes is measured concerning standard hydrogen electrodes.

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

The reaction's activation energy is relatively high at room temperature and not readily available, the reaction is highly viable. H₂ (g) and O₂ (g)bond break and clash, allowing particles to pass across the energy barrier.

2H₂ + O₂→2H₂O

Because of the large activation energy, the water molecule does not form in this equation.

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

Ans: Conductivity due to the total number of ions present in the solution is termed as specific conductivity. An increase in the number of ions per unit volume increases. In addition to water, the number of ions per unit volume decreases therefore conductivity decreases.

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

A. The reaction has a zero order. The concentration of the reactants does not change with time in a zero order reaction, and the rate of concentration remains constant

B. Slope of the curve is  - k

C. The rate constant's units are molL  ¹s ^{- 1}

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

Ans: pH of the substance depends on the concentration of hydronium ions present. Here the concentration of hydronium ions remains constant so pH remains constant.

The electrolysis reaction is as follows;

At anode: 2H₂O (l)→O₂ (g)+ 4H⁺ + 4e−

At cathode:4H⁺ + 4e⁻ →2H₂

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

Ans: Stronger electrolytes undergo cent percent dissociation. Electrolyte B will be the stronger electrolyte since the concentration of ions remains the same upon dilution.

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

Ans: The number of ions present in the cell decides the life-time of any cell. In mercury cells, ions are not involved so the mercury cell has a constant cell potential throughout its useful life.

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

Ans: Electrolysis of brine solution is as follows

NaCl (aq)→Na⁺ (aq)+Cl⁻ (aq)

At the cathode, the reaction goes this way,

H₂O (l) + e⁻→12H₂ (g)+OH⁻ (aq)

At the anode, the reaction goes this way,

Cl⁻ (aq)→12Cl₂ (g) + e⁻

The pH of the solution will increase as sodium hydroxide is being formed.