Chemistry 2017-2018 HSC Science (General) 12th Standard Board Exam Question Paper Solution

The process in which the value of ΔU = 0 is __

Adiabatic

Isothermal

Isobaric

Isochoric

An ionic crystal lattice has `r^+/r` radius ratio of 0.320, its coordination number is __

(a) 3

(b) 4

(c) 6

(d) 8

In the hydrogen-oxygen fuel cell, the carbon rods are immersed in the hot aqueous solution of __

(a) KCl

(b) KOH

(c) H₂SO₄

(d) NH₄Cl

The chemical formula of willemite is __

(a) ZnS

(b) ZnCO₃

(c) ZnO

(d) Zn₂SiO₄

The oxidation state of nitrogen in dinitrogen trioxide is ____

(a) + 1

(b) + 2

(c) + 3

(d) + 4

Which of the following 0.1 M will aqueous solutions exert highest osmotic pressure?

(a) `Al_2(SO_4)_3`

(b) `Na_2SO_4`

(c) `MgCl_2`

(d) KCl

The half-life period of zero order reaction A → product is given by

(a) `([A]_0)/k`

(b) `0.693/k`

(c) `[A]_0/(2k)`

(d) `(2[A]_0)/k`

Derive the relation between the elevation of boiling point and molar mass of solute.

State Third law of thermodynamics. Give ‘two’ uses.

Give two uses of the Third law of thermodynamics.

Draw a neat and labelled diagram of the lead storage battery.

Explain Ionic solids are hard and brittle.

A certain reaction occurs in the following steps-

\[\ce{Cl_g + O3(g)->ClO(g) +O2(g)}\]

\[\ce{ClO_g + O(g)->Cl(g) +O2(g)}\]

a) What is the molecularity of each of the elementary steps?

b) Identify the reaction intermediate and write the chemical equation for the overall reaction.

Define Semipermeable membrane

Define Reference electrode

What is the action of chlorine on CS₂

Answer the following.

What is the action of chlorine on Excess NH₃.

Write the chemical equations involved in van Arkel method for refining zirconium metal.

Write balanced chemical equations for Phosphorus reacts with magnesium

Write balanced chemical equations for Flowers of sulphur boiled with calcium hydroxide

Write balanced chemical equations for Action of ozone on hydrogen peroxide.

The density of iron crystal is 8.54-gram cm^–3. If the edge length of the unit cell is 2.8 A° and atomic mass is 56 gram mol^–1, find the number of atoms in the unit cell.  (Given: Avogadro's number = 6.022x10²³,1A° = 1x10^-8 cm)

How many faradays of electricity are required to produce 13 gram of aluminium from aluminium chloride solution? (Given: Molar mass of Al = 27.0-gram mol^–1)

Calculate the internal energy at 298K for the formation of one mole of ammonia, if the enthalpy change at constant pressure is – 42.0 kJ mol^-1.

(Given: R = 8.314 J K^-1 mol^-1)

Define the Enthalpy of atomization

Define Enthalpy of vaporization

Draw the structure of IF₇. Write its geometry and the type of hybridization.

State Henry’s law.

22.22 gram of urea was dissolved in 300 grams of water. Calculate the number of moles of urea and molality of the urea solution. (Given: a Molar mass of urea = 60 gram mol^-1)

What is the action of carbon on the following metal oxides:

Fe₂O₃ in the blast furnace

What is the action of carbon on the following metal oxides :

ZnO in the vertical retort furnace

Write the molecular and structural formulae of thiosulfuric acid.

Write the molecular and structural formulae of Dithionous acid

The reaction A + B → products is first order in each of the reactants

1) How does the rate of reaction change if the concentration of A is increased by factor 3?

2) What is the change in the rate of reaction if the concentration of A is halved and concentration of B is doubled?

A polymer used in paints is

(a) Nomex

(b) Thiokol

(c) Saran

(d) Glyptal

The number of primary and secondary hydroxyl groups in ribose are -

(a) 1, 3

(b) 2, 3

(c) 3, 1

(d) 3, 2

The ligand diethylene triamine is -

(a) monodentate

(b) bidentate

(c) tridentate

(d) tetradentate

Propene on oxidation with diborane in presence of alkaline hydrogen peroxide gives

(a) propane-1- ol

(b) propane-2-ol

(c) allyl alcohol

(d) propane-1, 2-diol

Baeyer’s reagent is -'

(a) acidified potassium dichromate

(b) alkaline potassium dichromate

(c) alkaline potassium permanganate

(d) acidified potassium permanganate

Identify 'A' in the following reaction -

(a) 2- Bromo-2 methylbutane

(b) 1 -Bromo-2,2-dimethylpropane

(c) 1 - Bromo - 3 -methylbutane

(d) 1 - Bromo- 2 -methylpropane

An antifertility drug is -

(a) Novestrol

(b) Histamine

(c) Vernal

(d) Equanil

Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
 in basic medium.

Explain the geometry of `[Co(NH_3)_6]^(3+)` on the basis of hybridisation. (Z of Co = 27)

Why ethanol has the higher boiling point than ethane?

Write only reactions for the preparation of benzophenone from benzonitrile.

What is the action of p-toluenesulphonychloride on ethylamine and diethylamine?

What are amino acids?

Write the correct reaction for formation of the peptide bond between amino acids

Explain the term Antiseptics

Define antioxidants?

Explain only reaction mechanism for alkaline hydrolysis of tert-butyl bromide

Complete and rewrite the balanced chemical equations

Complete and rewrite the balanced chemical equations

Complete and rewrite the balanced chemical equations

Butanone + 2, 4-dinitro-phenylhydrazine 

How carbolic acid is prepared from benzene sulphonic acid ?

Write a chemical equation for the action of neutral ferric chloride on phenol.

Explain the preparation and uses of nylon-2-nylon-6.

How is glucose prepared from cane sugar?

Write the formula of the complex copper (II) hexacyanoferrate (II).

What is Lanthanoid contraction?

Explain the cause of Lanthanoids contraction.

Draw the structures of chloroxylenol

Draw the structures of adenine.

How are ethylamine and ethyl methyl amine distinguished by using nitrous acid?

What is the action of the following reagents on ethanoic acid?

1) `LiAlH_4"/"H_3O^+`

2) `PCl_3 , "heat"`

3) `P_2O_5, "heat"`

Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :

Write a short note on Hoffmann bromamide degradation.