Short Answer TypeHow will you bring about the following conversions :
(i) Acetaldehyde to acetamide.
(ii) Phenol to benzoic acid
(iii) Glucose to saccharic acid.
How will you distinguish between the following pairs of compounds ? (Give one good chemical test.)
(i) Ethylamine and Acetamide
(ii) Oxalic acid and Acetic acid.
What type of polymerisation takes place when a polyester is formed? Give one example of a polyester and name the monomers from which it is formed.
(ii) Give two examples of natural polymers.
Give balanced equations for the following reactions:
(i) Formic acid heated with Tollen’s reagent.
(ii) Phenol heated with chloroform and sodium hydroxide.
(iii) Acetaldehyde reacted with phenyl hydrazine.
(iv) Aniline treated with benzoyl chloride.
Long Answer Typei) Write the mathematical expression for the first law of thermodynamics.
One mole of an ideal gas is expanded isothermally against a constant pressure of 3 atmospheres from 10 litres to 35 litres. Calculate the work done, change in internal energy and heat absorbed during the process.
(ii) Calculate the free energy change of the reaction:
C(graphite)+O2 (g) →CO2(g) ΔH = - 300 kJ mol-1 and AS = 3JK-1 mol-1 at 300 K.
Predict whether the reaction is spontaneous or not at 300 K.
i) Mathematical expression for first law of thermodynamics
ΔE = q + w
where ΔE = change in internal energy
q = Heat supplied to system,
w = Work done on the system,
w = pΔV
= 3 x 105 x (35 - 10)
= 75 x 105 J
Change in internal energy is zero for isothermal process.
Heat absorbed = 75 x 105 x 4.18 J
= 313.5 Cal
(ii) ΔG = ΔH - TΔS
= - 300 - 300 x 3
= - 300 - 900
= - 1200 kJ
Since the sign of AG is negative the reaction is spontaneous.
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