In Rutherford’s experiment, generally the thin foil of heavy atoms, like gold, platinum etc. have been used to be bombarded by the α-particles. If the thin foil of light atoms like aluminium etc. is used, what difference would be observed from the above results ?

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Aluminium forms the ion Al³⁺ , but not Al ⁴⁺  why?

2

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Discuss the hybridisation of Be in gaseous state and solid state.

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Use the information and data given below to answer the question, stronger intermolecular forces result in higher boiling point.
Strength of London forces increases with the number of electrons in the molecules. Boiling point of HF, HCI, HBr, and HI are 293 K, 189 K, 206 K and 238 K respectively.
Looking at the trend of boiling points of HCI, HBr, and HI, explain out of dipole-dipole interaction and London interaction, which one is predominant here.

2

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Use the information and data given below to answer the question, stronger intermolecular forces result in higher boiling point.
Strength of London forces increases with the number of electrons in the molecules. The boiling point of HF, HCI, HBr, and HI are 293 K, 189 K, 206 K and 238 K respectively.
Why is the boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?

2

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Why standard entropy of an elementary substance is not zero whereas standard enthalpy of formation is taken as zero?

2

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Calculate the free energy change when 1 mole of NaCl is dissolved in water at 298 K. (Given, lattice energy of NACl = -777.8 kJ mol^-1 , hydration energy = -774.1 kJ mol^-1 and \(\Delta S=0.043kJ \ K^{ -1 }mol^{ -1 }\) at 298 K).

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Give reasons.
A mixture of dilute NaOH and aluminium pieces is used to open drain.

2

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A compound A of boron reacts with NMe₃ to give an adduct B which on hydrolysis gives a compound C and hydrogen gas. Compound C is an acid. Identify the compounds A, B and C. Give the reactions involved.

2

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Carbon monoxide is readily absorbed by ammonical cuprous chloride solution but carbon dioxide is not. Explain.

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