HSC Science (Computer Science) १२ वीं कक्षा - Maharashtra State Board Question Bank Solutions for Chemistry

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)

Calculate emf of the following cell at 25 °C :

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

E°(Fe²⁺| Fe)= −0.44 V E°(H⁺ | H₂) = 0.00 V

A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.

(log 2 = 0.3010)

Write the hybridization and shape of the following complexe : [CoF₆]^3–

(Atomic number : Co = 27, Ni = 28)

Write the hybridization and shape of the following complexe : [Ni(CN)₄]^2–

^{(Atomic number : Co = 27, Ni = 28)}

Calculate the freezing point of the solution when 31 g of ethylene glycol (C₂H₆O₂) is dissolved in 500 g of water.

(K_f for water = 1.86 K kg mol^–1)

Calculate e.m.f. and ∆G for the following cell:

Mg (s) |Mg²⁺ (0.001M) || Cu²⁺ (0.0001M) | Cu (s)

`"Given :" E_((Mg^(2+)"/"Mg))^0=−2.37 V, E_((Cu^(2+)"/"Cu))^0=+0.34 V.`

Draw the structure of: Pyrophosphoric acid

Write the electronic configuration of the following elements:

Sulphur (Z = 16)

When primary amine reacts with CHCl3 in alcoholic KOH, the product is _______.

(A) aldehyde

(B) alcohol

(C) cyanide

(D) an isocyanide