Chemistry 56/3/2 2018-2019 Science (English Medium) Class 12 Question Paper Solution

Write IUPAC name of the complex K3 [Cr (C₂O₄)3] 

Using IUPAC norms write the formula of Hexaamminecobalt (III) sulphate. 

Why is CH₂ = CH - CH₂ - Cl more easily hydrolysed than CH₃ - CH₂ - CH₂ - Cl ?

Write the IUPAC name of the follow

\[\begin{array}\ce{\phantom{--..}O}\\\ce{\phantom{--..}||}\\ \ce{CH2=CH-C-CH3}\end{array}\]

What is the difference between a glycosidic linkage and a peptide linkage? 

What is the difference between a glycosidic linkage and a peptide linkage? 

 Arrange the following increasing order of their boiling point:
CH₃CH₂OH, CH₃CHO, CH₃–O–CH₃ 

 What happens when AgCl is doped with 2? CdCl What is the name of this defect? 

What type of defect is shown by NaCl in 
 stoichiometric defects, and

 non-stoichiometric defects?

Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.

 Account for the following: 
On reaction with benzene sulphonyl chloride, primary amine yields product soluble in alkali whereas secondary amine yields product insoluble in alkali.

 Complete and balance the following equations: 
S+H₂SO₄(conc.)  → 

 Complete and balance the following equations: 
PCL₃ + H₂O → 

Write balanced chemical equations involved in the following reactions:
Chlorine gas reacts with cold and dilute NaOH 

Write balanced chemical equations involved in the following reactions: 
Calcium phosphide is dissolved in water. 

 Draw structures of the following: 
XeF₄ 

 Draw structures of the following: 
`S_2O_8^{2-}`

 Write the reaction that occurs at anode on electrolysis of concentrated 2 4 H SO using platinum electrodes. 

What is the effect of temperature on ionic conductance? 

 Out of 0.1 molal aqueous solution of glucose and 0.1 molal aqueous solution of KCl, which one will have higher boiling point and why? 

 Predict whether van’t Hoff factor, (i) is less than one or greater than one in the following: 
CH₃COOH dissolved in water 

Write structures of compounds A and B in each of the following reactions: 

 Write structures of compounds A and B in each of the following reactions:

Define the following with a suitable example, of each: 
 Coagulation 

Define the following with a suitable example, of each: 
Multimolecular colloid

 Define the following with a suitable example, of each: 
 Gel

Out of starch and ferric hydroxide sol, which one can easily be coagulated and why? 

What is observed when an emulsion is centrifuged?

 What is the role of promoters and poisons in catalysis?

 Following reaction takes place in the cell: 
`Zn(s) + Ag_2O(s)+H_2O(l) -> Zn^{2+}(aq) + 2Ag (s) + 2OH^- (aq)`
Calculate `Delta_r G^0` of the reaction

[Given ; `E^0_(Zn^{2+}//Zn)` = -0.76V

`E_((Zn^{2+}//Zn)) = 0.76V`

`E_(Ag^4//Ag)^0 = 0.80V, 1F = 96,500 C mol^-1 ]`
          

 How can you determine limiting molar conductivity,   0 m for strong electrolyte and weak electrolyte?

Write down the reaction taking place in blast furnace related to the metallurgy of iron in the temperature rnge 500 K – 800 K. What is the role of limestone in the metallurgy of iron? 

What happens when Silver is leached with NaCN in the presence of air? 

What happens when Copper matte is charged into silica lined converter and hot air blast is blown? 

What happens when Silver is leached with NaCN in the presence of air? 

 A solution 0.1 M of Na₂SO₄ is dissolved to the extent of 95%. What would be its osmotic pressure at 027 ? C (R = 0.0821 L atm K^-1 mol^-1) .

 An element crystallises in bcc lattic with a cell edge of 3 × 10^-8cm. The density of the element is 6.89 g cm^-3 . calculate the molar mass of element. (N_A = 6.022 × 10²³ mol^-1)

What type of semiconductor is obtained when 
Ge is doped with In?

 What type of semiconductor is obtained when 
 Si is doped with P? 

 Give reactions for the following: 
O – O single bond is weaker than S – S single bond. 

 Tendency to show –3 oxidation state decrease from Nitrogn (N) to Bismuth (Bi).

 Cl2 acts as a bleaching agent. 

Write the structures of monomers used the following polymers:
Buna S

Write the structures of monomers used the following polymers:
Glyptal

Write the structures of monomers used to obtain the following polymers: 
 Nylon-6

Arrange the following polymers in increasing order of their intermolecular forces: 
Polyvinylchloride, Neoprene, Terylene

 Write one example each of :
 Natural polymer 

 Write one example each of :
Thermosetting polymer 

What is the significance of number of 6,6 in the polymer nylon-6,6?

Which one of the following is a disinfectant?
0.2% solution of phenol or 1% solution of phenol 

 What is the difference between agonists and antagonists? 

Write one example each of Artificial sweetener.

Write one example each of Antacids.

Define the following terms with a suitable example of each: 
 Antiseptics 

Define the following terms with a suitable example of each: 
 Bactericidal antibiotics 

Define the following term with a suitable example: 
Cationic detergents

What happens when Salicylic acid is treated with (CH₃CO)₂ O/H⁺?

What happens when Phenol is oxidised with Na₂Cr₂O₇/H⁺?

What happens when Anisole is treated with CH₃Cl/anhydrous  AlCl₃?

Write chemical equation in support of your answer. 
 Out of   Cl and  CH₂- Cl,  which one is more reactive towards nucleophilic substitution reaction and why? 

Write chemical equation in support of your answer. 
 Out of  Cl and O2N Cl. which one is more reactive  towards nucleophilic substitution reaction and why?

 Out of    _{and  , which one is optically active and why ?}

Give one chemical test as an evidence to show that [Co (NH₃)₅Cl]  are ionisation isomers. 

[NiCl₄]^2- is paramagnetic while [Ni(CO)₄] is  diamagnetic though both are tetrahedral. Why? (Atomic no. Ni = 28) 

 Write the electronic configuration of Fe(III) on the basis of crystal field theory when it forms an octahedral complex in the presence of (i) strong field, and (ii) weak field ligand. (Atomic no.of Fe=26) 

What is the difference between fibrous protein and globular protein ?

Differentiable between the following: 
Essential amino acids Non-essential amino acids 

Differentiable between the following: 
Amylose and Amylopectin 

Account for the following : 
Manganese shows maximum number of oxidation states in 3d series. 

E⁰ value for  Mn³⁺ Mn²⁺ couple is much more positive than that for Cr^3-/ Cr^2-.

Account for the following : 
 Ti⁴⁺ is colourless whereas V⁴⁺  is coloured in an aqueous solutions. 

 Write the chemical equation for the preparation of 4 KMnO from 2. MnO Why does purple colour of acidified permanganate solution decolourise when it oxidises Fe^2- to Fe³⁺ ? 

Write one difference between transition elements and p-block elements with reference to variability of oxidation states.

Why do transition metals exhibit higher enthalpy of atomization? 

Name an element of lanthanoid series which is well knwon to shown +4 oxidation state. Is it a strong oxidising agent or reducing agent? 

What is lanthanoid contraction? Write the.............

 Write the ionic equation showing the oxidation of Fe(II) salt by acidified dichromate solutions. 

Define order of reaction. How does order of a reaction differ from molecularity for a complex reaction? 

 A first order reaction is 50% complete in 25 minutes. Calculate the time for 80% completion of the reaction.

The decomposition of a hydrocarbon has value of rate constant as 2.5×10⁴s^-1 At 27° what temperature would rate constant be 7.5×10⁴ × ³ s^-1if energy of activation is  19.147 × 10³ J mol^-1 ?

 Write a condition under which a bimolecular reaction is kinetically first order. Give an example of  such a reaction. (Given : log2 = 0.3010,log 3 = 0.4771, log5 = 0.6990).

 Predict the main product of the following reactions:

 Predict the main product of the following reaction:\[\begin{array}{c}
\ce{O\phantom{----}O\phantom{-}}\\
\ce{||\phantom{----}||\phantom{-}}\\
\ce{CH3-C-CH2-C-OCH3}
\end{array}\ce{->[(i)NaBH4][(ii)H+]}\]

Predict the main product of the following reactions:
\[\ce{CHO + CH_3CHO->[dil NaOH]}\]

Give a simple chemical test to distinguish between 
 

 Why is alpha (α) hydrogen of carbonyl compounds acidic in nature?

Write the main product formed when propanal reacts with the following reagents: 
2 moles of 3 CH OH in presence of dry HCl 

 Write the main product formed when propanal reacts with the following reagents: 
(ii) Dilute NaOH 
`CH_3CH_2CHO + NaOH(dil)-> `

Write the main product formed when propanal reacts with the following reagents: 
H₂N- NH₂  followed by heating with KOH in ethylene glycol. 

 Arrange the following compounds in increasing order of their property as indicated:
 F - CH₂COOH, O₂N - CH₂ COOH CH₃ COOH,HCOOH - acid character. 

 Acetone, Acetaldehyde, Benzaldehyde, Acetophenone – reactivity towards addition of HCN.