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

Describe laboratory method for preparation of glucose.

State and explain Markownikoff's rule with suitable example

For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.

 A first order reaction takes 40 minutes for 30% decomposition. Calculate t_1/2 for this reaction. (Given log 1.428 = 0.1548)

In body centred cubic structure the space occupied is about

(A) 68%                                                     (B) 53%

(C) 38%                                                     (D) 32%

Which of the following solutions shows maximum depression in freezing point?

(A) 0.5 M Li₂SQ₄

(B) 1 M NaCl

(C) 0.5 M A1₂(SO₄)₃

(D) 0.5 MBaC1₂

The standard e.m.f of the following cell is 0.463 V

`Cu|Cu_(1m)^(++)`

What is the standard potential of Cu electrode?

(A) 1.137 V

(B) 0.337 V

(C) 0.463 V

(D) - 0.463 V

Draw structure and write geometry of PCl₃ and PCl_5.

Prove that ΔH=ΔU+ΔnRT. what is the condition under which ΔU=ΔH?

Prove that ΔH=ΔU+ΔnRT. what is the condition under which ΔU=ΔH?

How is 4-methylpent-3-en-2-one obtained from propan-2-one?

Write the structural formula and IUPAC names of all possible isomers of the compound with molecular formula C₃H₈O.

Calculate E°_cell for the following reaction at 298 K:

2Al_(s) + 3Cu⁺²(0.01M) → 2Al⁺³(0.01M) + 3Cu_(s)

Given: E_cell = 1.98V

Calculate the amount of CaCl₂ (molar mass = 111 g mol⁻¹) which must be added to 500 g of water to lower its freezing point by 2 K, assuming CaCl₂ is completely dissociated. (K_f for water = 1.86 K kg mol⁻¹)

Calculate emf of the following cell at 25°C:

\[\ce{Sn/Sn^2+ (0.001 M) || H+ (0.01 M) | H2_{(g)} (1 bar) | Pt_{(s)}}\]

Given: \[\ce{E^\circ(Sn^2+/sn) = -0.14 V, E^\circ H+/H2 = 0.00 V (log 10 = 1)}\]

A first order reaction takes 23.1 minutes for 50% completion. Calculate the time required for 75% completion of this reaction.

(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

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

2Cr(s) + 3Fe²⁺ (0.1M) → 2Cr³⁺ (0.01M) + 3 Fe(s)

Given: E°(Cr³⁺ | Cr) = – 0.74 VE° (Fe²⁺ | Fe) = – 0.44 V

Calculate the freezing point of solution when 1.9 g of MgCl₂ (M = 95 g mol⁻¹) was dissolved in 50 g of water, assuming MgCl₂ undergoes complete ionization.

(K_f for water = 1.86 K kg mol⁻¹)

When 2.56 g of sulphur was dissolved in 100 g of CS₂, the freezing point lowered by 0.383 K. Calculate the formula of sulphur (S_x).

(K_f for CS₂ = 3.83 K kg mol⁻¹, Atomic mass of sulphur = 32 g mol⁻¹]

Write the hybridization and magnetic behaviour of the complex [Ni(CO)₄].

(At.no. of Ni = 28)