HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Chemistry

The depression in freezing point of water observed for the same amount of acetic acid, trichloroacetic acid and trifluoroacetic acid increases in the order given above. Explain briefly.

Answer the following in one sentence:

Why is it necessary to add \[\ce{H2SO4}\] while preparing the solution of \[\ce{CuSO4}\]?

Answer the following in one sentence:

Why is it necessary to add \[\ce{H2SO4}\] while preparing the solution of \[\ce{CuSO4}\]?

How is enthalpy of sublimation related to enthalpy of fusion and enthalpy of vaporization?

Explain the mechanism of esterification

Define the Enthalpy of fusion

Define the Enthalpy of atomization.

Draw structure of DDT.

Define ebullioscopic constant.

If the enthalpy of vaporisation of water at 100^oC is 186.5 J.mol^-1, the entropy of vaporization will be_____________ .

(a) 4.0 J . K^-1. mol-¹                                               

(b) 3.0 J . K^-l.  mol^-1

(c) 1.5 J - K^-1. mol-¹                                             

(d) 0.5 J . K^-l. mol^-1

Which of the following is polyamide ?

(a) Teflon

(b) Nylon  6,6

(c) Terylene

(d) Bakelite

Write the reaction that indicates the presence of -CHO group in glucose

Draw the simple Fisher projection formulae of D - (+) - glucose and D - (-) - fructose

How is Nylon 6, 6 prepared?

Determine the osmotic pressure of a solution prepared by dissolving 2.5 × 10⁻² g of K₂SO₄ in 2L of water at 25°C, assuming that it is completely dissociated.

(R = 0.0821 L atm K⁻¹ mol⁻¹, Molar mass of K₂SO₄ = 174 g mol⁻¹)

Calculate the e.m.f. of the following cell at 298 K:

Fe(s) | Fe²⁺ (0.001 M) | | H⁺ (0.01 M) | H₂(g) (1 bar) | Pt(s)

Given that \[\ce{E^0_{cell}}\] = 0.44 V

[log 2 = 0.3010, log 3 = 0.4771, log 10 = 1]

Which of the following compounds contain S = O as well as S = S bonds?

(A) Sulphuric acid

(B) Thiosulphuric acid

(C) Sulphurous acid

(D) Thiosulphurous acid

For a chemical reaction dS=0.035 kJ/k and dH=20kJ. At what temperature does the reaction turn nonspontaneous?

A system absorbs 640 J heat and does work of 260 J, the change in internal energy of the system will be

(a) +380J

(b) -380J

(c) +900J

(d) -900J

Which of the following is not a colligative property?