HBSE 12th Chemistry Paper 2024

Q.1 In comparison to a 0.01M solution of glucose, the depression in the freezing point of 0.01 M MgCl2 is

Q.2 Rate law for the reaction A + 2B ——- C is found to be Rate = K[A][B]. Concentration of reactant B ia doubled keeping the concentration of A constant, the value of rate constant will be-

Q.3 Which of the following oxidation state is common for all Lanthanoids?

Q.4 The reagent which does not react with both acetone and benzaldehyde:

Q.5 The value of Henry’s constant K_H :

Q.6 Which of the following B-group vitamin can be stored in our body?

Q.7 An electrochemical cell can behave like an electrolyte cell, when :

Q.8 The gas evolved when methyl amine reacts with nitrous acid is :

Q.9 Activation energy of a chemical reaction can be determined by

Q.10 Cannizzaro’s reaction is not given by

Q.11 When alkaline KMnO₄ is treated with KI, iodide ion is oxidized to

Q.12 Which of  the following is most acidic?

Q.13 The CFSE for octahedral [CoCl₆]­^4-  is 18000 cm_­^-1. . The CFSE for tetrahedral [CoCl₄]^2-  will be

Q.14 toluene reacts with a halogen in the presence of iron{III} chloride giving ortho and para halo compound the reaction  is

Q.15 Assertion [A]:-The  boiling  point of alkyl halides decreases in the  order RI > RBr > RCl > RF for same alkyl group.
Reason[R]:-  The boiling  point of  alkyl halide having chloride , bromide  and  iodide  are higher than that of the hydrocarbon of comparable molecular mass.

Q.16 Assertion[A]:- formaldehyde is a planar molecule.
Reason[R]:- It contains  sp² hybridized carbon atom.

Q.17 Assertion[A]:- when  NaCl is added to water, a depression in freezing point is observed.
Reason[R]:- the lowering of vapour pressure of a solution causes depression in the freezing point.

Q.18 Assertion[A]:-complexes of   MX₆ and MX₅L type [ X and L are unidentate ] do not show geometrical isomerism
Reason[R]:-geometrical isomerism is not shown by complexes of co- ordination no 6.

Q.19 Which alkyl halide from the following pair would you expect to react more rapidly by SN² mechanism.

Q.20 What is the effect of denaturation on the structure of protein.

Q.21 For the reaction R—- > P the concentration of a reactant changes from 0.03M to 0.02M in  25 minutes. Calculate the average rate of reaction using units of time in minute.

OR
 The time required to decompose SO₂Cl₂ to half of its initial amount is 60 minute. If the decomposition is a first order reaction, then calculate the rate constant.

Q.22 Write the IUPAC name of the following coordination compounds:-

Q.23 What happens, when:-

Q.24 Explain how does OH group attached to a carbon of benzene ring activate it towards electrophilic substitution reaction.

OR
Estimate the products obtained from the following reaction  

Q.25 give the structure of A and B in the following reaction.

Q.26  Explain the variation of molar conductivity of a strong electrolyte and weak electrolyte with concentration through graph

Q.27 what is a crystal field splitting energy? How does a magnitude of ∆_o decide the actual configuration of  d orbital in coordination  entity having d⁴ configuration.

OR
Discuss the nature of bonding in a following coordination entities on the basis of VBT
(i) FeCN₆]⁴–
(ii) [CoF₆]³–

Q.28 Convert the following
(i) propan-2-ol to propan-2-one
(ii) Phenol to benzoquinone
(iii) Phenol into benzene.

Q.29 answer the following
{i}  Pkb of aniline is more than that of methylamine, why?
{ii} Convert benzyl chloride into 2-phenyletahaneamine.
{iii} Why do primary amines have higher boiling point than tertiary amines?

OR
(i) Write the IUPAC name of the amide that gives propanamine by Hoffmann’s Bromamide reaction.
(ii) Arrange the following in the increasing order of basic strength:
C₆H₅NH₂, NH₃, C₂H₅NH₂, (C₂H₅)₂NH
(iii) Give one test to distinguish between aniline and benzylamine

Q.30  For   the first order reaction show that the time required for 99% completion is twice the time required for the completion of 90%?

Q.31 Monosaccharide are the simple carbohydrates that can’t be broken further into smaller units on hydrolysis. For example glucose, fructose,  ribose etc. oligosaccharide are the carbohydrate which gives 2 to 10 units of monosaccharide. Eg. Sucrose, maltose, lactose etc. Polysaccharide gives large number of monosaccharide units on hydrolysis e.g starch, cellulose.
Questions:
(i) Name the linkage that holds the two units in the disaccharide?
(ii) Which disaccharide is found in animal only, not in plants?
(iii) Draw Haworth projection of α-D glucose.

Or
What is glycogen? How it is different from starch?
 

Q.32 Answer the questions-
 
(i) What happens when RBC are placed in 0.9% NaCl solution?
(ii) Which one of the following has higher osmotic pressure; 1M KCl or 1M urea?
(iii) What is reverse osmosis? Name one SPM which can be used in this reverse osmosis?

OR
How the molecular mass of substances can be determined by method based on measurement of osmotic pressure?

Q.33      (i)How does acidified permanganate solution react with oxalic acid? Write ionic equation for this reaction.
                 (ii) Why E⁰(M²⁺ | M)   value of copper is positive value?
(iii)Compare Lanthanoids and Actinoids with special reference to electronic configuration, oxidation state and atomic and ionic size?

Or
(i) Why transition elements have the high enthalpy of atomization?
(ii) Why highest oxidation state is exhibited in oxoanions of a metal?
(iii) Indicates the steps in the preparation of K₂Cr₂O₇ from the chromite ore.

Q.34      (i) Write the structure of product of the following reaction
                (ii) Draw the structure of cyclo-propanone oxime?
                (iii) There are two NH₂ groups in semicarbazide, but only one is involved in semicarbazone formation, why?
                (iv) Arrange the following compounds in increasing order of reactivity toward HCN:
                                Acetaldehyde,  Acetone,  Ditertbutyl Ketone.
                (v) Write a short note on Aldol condensation.

Or
An organic compound with formula C₉H₁₀O form 2,4-DNP. Derivate reduce Tollen’s reagent and undergoes Cannizzaro’s reaction. On vigorous oxidation, it gives 1,2 benzene dicarboxylic acid. Identify the compound. Write its IUPAC name. Write all chemical reaction involved in reaction.

Q. 35     (i) Calculate the standard cell potential of galvanic cell in which the following reactions take place. Also calculate the value of ∆G⁰ of the reaction.
                (ii) Define kohlrausch’s law by taking suitable example?

(i) Write Nernst equation and calculate the emf of the following cell at 298 K:
Mg|Mg²⁺ (0.001M) || Cu²⁺ (0.0001M)| Cu
E⁰ for Mg = -2.37 V
E⁰ for Cu =  0.34 V
 
(ii) Why conductivity of a solution decreases with dilution.