Subject

Chemistry

Class

ICSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsShort Answer Type

Advertisement

21.

i) Define molar conductance of a solution. State its unit. How is it related to the specific conductance of a solution ?

ii) Calculate the value of Ecell at 298K for the following cell:

Al|Al3+ (O.OIM)|| Sn2+(0.015M)|Sn

E° Al+3/Al = -1.66 volt and [E0 sn2+/Sn, = -0.14 volt]


i) Molar conductance of a solution is defined as the conducting power of all the ions produced by dissolving one mole of an electrolyte. Its unit is ohm-1 cm2 mol-1

straight capital lambda subscript straight m space equals fraction numerator 1000 space straight x space straight k over denominator straight C end fraction

Where space straight C space is space the space molarity space of space the space solution

ii) 

straight E subscript cell superscript 0 space equals space left parenthesis straight E subscript reduction superscript 0 right parenthesis space cathode minus space left parenthesis straight E subscript oxidation superscript 0 right parenthesis space anode
space space space equals space left parenthesis negative 0.14 right parenthesis minus left parenthesis 1.66 right parenthesis space volt space equals space 1.52 space volt

The space balanced space equation space of space reaction space is space colon
space 2 Al space plus 3 Sn to the power of 2 plus end exponent rightwards arrow with space space space space space on top space 2 Al to the power of 3 plus end exponent space plus Sn space left parenthesis straight n equals 6 right parenthesis

By space using space the space nernst space equation comma

straight E subscript cell equals straight E subscript cell superscript 0 space minus fraction numerator 0.05912 over denominator straight n end fraction space log space fraction numerator left square bracket products right square bracket over denominator left square bracket reactant right square bracket end fraction
straight E subscript cell space equals space 1.52 space minus fraction numerator 0.05912 over denominator 6 end fraction log space fraction numerator left square bracket Al to the power of 3 plus end exponent right square bracket squared left square bracket Sn right square bracket over denominator left square bracket Sn to the power of 2 plus end exponent right square bracket cubed left square bracket Al right square bracket squared end fraction
straight E subscript cell space equals space 1.52 minus fraction numerator 0.05912 space over denominator 6 end fraction log fraction numerator left parenthesis 0.01 right parenthesis squared left parenthesis 1 right parenthesis squared over denominator left parenthesis 0.015 right parenthesis cubed left parenthesis 1 right parenthesis squared end fraction

space equals space 1.52 minus 0.0145 space equals space 1.5055 space volt

Ecell = 1.5055 volt


721 Views

Advertisement
22.

(i) Calculate the degree of hydrolysis of 0.2(M) sodium acetate solution.

(Hydrolysis constant of sodium acetate = 5.6x 10 -10 and ionic product of H20 = 10 -14 at 25°C )

(ii) Explain why high pressure is used in the manufacture of ammonia by Haber’s process. State the law or principle used.

1729 Views

23.

Give the IUPAC names of the following coordination compounds :

(i) K2[Zn(OH)4]

(ii) [Co(NH3)5(Co3)]Cl

1193 Views

24.

For the complex ion [Fe(CN)6]3- state :

(i) The geometry of the ion.

(ii) The magnetic property of the ion.

763 Views

Advertisement
25. What type of structural isomers are [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br ? Give a chemical test to distinguish the isomers.
4503 Views

26.

For the molecule XeF2.

(i) Draw the structure of the molecule indicating the lone pairs.

(ii) State the hybridisation of the central atom.

(iii) State the geometry of the molecule.

703 Views

27.

Give balanced chemical equations for the following reactions:
(i) Fluorine treated with dilute sodium hydroxide solution.
(ii) Hydrogen sulphide treated with concentrated sulphuric acid.
(iii) Potassium iodide treated with acidified potassium permanganate solution.

567 Views

28.

 In the extraction of zinc from zinc how oxide is converted to zinc.  

(i) Give an equation to show how zinc oxide is converted to zinc.

(ii) How is impure zinc finally electro-refined.

912 Views

Advertisement
29.

Explain why:

(i) Transition elements form coloured compounds.

(ii) Interhalogen compounds are more reactive than their constituent elements.

(iii) Cu+ is diamagnetic but Cu2+ is paramagnetic. (Z = 29).

988 Views

30.

How can the following conversions be brought about:   

(i) Nitro benzene to benzene diazonium chloride.

(ii) Propanoic acid to ethylamine.

(iii) Benzoic acid to benzaldehyde

614 Views

Advertisement