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

Explain the nature of zinc oxide with the help of the reactions.

Absolute entropies of solids, liquids and gases can be determined by

• Measuring heat capacity of substance at various temperatures
• Subtracting standard entropy of reactants from products
• Measuring vibrational motion of molecules
• Using formula ΔS° = S_T° - S_O°

The determination of molar mass from elevation in boiling point is called as

• cryoscopy
• colorimetry
• ebullioscopy
• spectroscopy

 How is propene converted into 1- bromopropane and 2 - bromopropane?

The preparation of alkyl fluoride from alkyl chloride, in presence of metallic fluorides is known as ______________.

Colligative property depends only on ........................ in a solution.

Draw neat and labelled diagram of dry cell.

Determine whether the reactions with the following ΔH and ΔS values are spontaneous or non-spontaneous. State whether the reactions are exothermic or endothermic.

(a) ΔH = -110kJ, ΔS = + 40JK^-1 at 400 K

(b) ΔH = + 40kJ, ΔS = -120JK^-1 at 250K

Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law with `t_(1/2)` = 3 hours. What fraction of the sample of sucrose remains after 8 hours?

Niobium crystallises as body centred cube (BCC) and has density of 8.55 Kg / dm^-3 . Calculate the attomic radius of niobium.

(Given : Atomic mass of niobium = 93).

What is the geometry of chromate ion?

1. Tetrahedral                    
2. Octahedral
3. Trigonal planer              
4. Linear

Identify the strongest acid amongst the followings:

1. Chloroacetic acid          
2. Acetic acid
3. Trichloroacetic acid
4. Dichloroaceticacid

Write a note on Friedel Craft’s acylation.

Explain, why are boiling points of carboxylic acids higher than corresponding alcohols

A solution of glucose in water is labelled as 10% (W/W).

Calculate:

a. Molality

b. Molarity of the solution.

[Given: Density of solution is 1.20 g mL^-1 and molar mass of glucose is 180 g mol^-1 ]

Write ‘four’ uses of hydrochloric acid.

What is the molecular formula of chromyl chloride?

(A) CrO₂Cl₂

(B) CrOCl₂

(C) CrCl₃

(D) Cr₂OCl₂

A solution containing 0.73 g of camphor (molar mass 152 g . mol^-1) in 36.8 g of acetone (boiling point 56.3°C) boils at 56.55°C. A solution of 0.564 g of unknown compound in the same weight of acetone boils at 56.46^oC. Calculate the molar mass of the unknown compound.

What is the action of acidified potassium dichromate on - SO₂

Draw structure of dichromate ion