HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

Why is Nickel-cadmium cell referred to as a secondary cell?

Write working of NICAD storage cell. Also write its applications.

Effect of catalyst in a chemical reaction is to change the _______.

Sulfur dioxide reacts with sodium hydroxide solution to form _______.

The number of lone pairs of electrons present in ClF₅:

Draw structure and name the shape of bromine trifluoride.

Explain the trend in the following atomic properties of group 16 elements:

Electron gain enthalpy

The standard enthalpy of formation of water is - 286 kJ mol^-1. Calculate the enthalpy change for the formation of 0.018 kg of water.

Calculate enthalpy of formation of HCl if bond enthalpies of H₂, Cl₂ and HCl are 434 kJ mol^-1, 242 kJ mol^–1 and 431 kJ mol^–1 respectively.

Define the Standard enthalpy of combustion.

State and explain Hess’s law of constant heat summation.

The enthalpy change of the following reaction:

\[\ce{CH_{4(g)} + Cl_{2(g)} -> CH3Cl_{(g)} + HCl_{(g)}ΔH^0 = –104 kJ}\]

Calculate C – Cl bond enthalpy. The bond enthalpies are:

Calculate the standard enthalpy of combustion of CH_4(g) if Δ_fH°(CH₄) = – 74.8 kJ mol^–1, Δ_fH°(CO₂) = – 393.5 kJ mol^–1 and Δ_fH°(H₂O) = – 285.8 kJ mol^–1.

Define standard enthalpy of formation.

Write the name of biodegradable polymer formed by two amino acids namely glycine and ε-amino caproic acid.

Write the name of raw material used for preparation of nylon 6, 6 polymer.

Calculate the standard enthalpy of formation of liquid methanol from the following data:

1. \[\ce{CH3OH_{(l)} + \frac{3}{2} O_{2(g)} -> CO_{2(g)} + 2H2O_{(l)}}\]     ∆H° = – 726 kJ mol^–1
2. \[\ce{C_{(Graphite)} + O_{2(g)} -> CO_{2(g)}}\]          ∆_cH° = – 393 kJ mol^–1
3. \[\ce{H_{2(g)} + \frac{1}{2} O_{2(g)} -> H2O_{(l)}}\]          ∆_fH° = – 286 kJ mol^–1 

Define the Bond enthalpy.

Calculate the standard enthalpy of the reaction.

\[\ce{2Fe_{(s)} + \frac{3}{2} O_{2(g)} -> Fe2O_{3(s)}}\]

Given:

Define the Enthalpy of ionisation.