PSEB Punjab Board Class 12 Chemistry Model Test Paper 2025: Download Sample Paper for Free

Q1. Choose the correct answer

i.An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because-

a.It gains water due to osmosis. 

b.It loses water due to osmosis.

c.It gains water due to reverse osmosis.

d.It loses water due to reverse osmosis. 

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

a.The same 

b.About twice

c.About three times 

d.About six times 

iii.a-Isotonic solution have 

a.same boiling point 

b.same vapour Pressure 

c.Same melting point 

d.Same osmotic Pressure

iv.What is the final oxidation state of manganese after the electrochemical reactions in a Dry Cell? 

a. +4

b.+3 

c. +2 

d.+1 

v.If the unit of specific rate constant (k) for a certain gaseous reaction is atm-2 s -1, then, the order of the reaction is-

a.Zero order 

b.First order

c.Second order 

d.Third order

vi.The coordination number of platinum in [PtCl2(C5H5N)(NH3)] is-

a.3

b.4

c.5

d.6

vii.The reaction of toluene with Cl₂ in the presence of FeCl₃ gives predominantly-

a.benzoyl chloride 

b.benzyl chloride 

c. m-chlorotoluene 

d.o- and p- chlorotoluene 

viii.Which of the following is most reactive towards nucleophilic addition reactions? 

a.CH3COCH3 

b.CH3CHO 

c.CH3COC2H5 

d.HCHO 

 ix.Which of the following reagents cannot be used to distinguish between pentanal and 2-pentanone?

a.Tollen’s reagent 

b.Fehling’s solution 

c.Br2 in CCl4 

d.I2 in NaOH 

x.Which of these is most acidic?

a.CF3COOH

b.CCl3COOH 

c. CBr3COOH

d.CH3COOH 

True/False 

(xi) The compounds [Co Cl2 (NH3)4] NO2 and [Co Cl (NO2) (NH3)4] Cl show coordination isomerism. 

(xii) The crystal field splitting Δo, depends on the field produced by the ligand and charge on the metal ion.  

(xiii) The boiling point of ethers are higher than those of isomeric alcohols.

(xiv) Benzaldehyde cannot undergo Cannizzaro reaction.

(xv) The red brown precipitate of Aldehydes with Fehling’s solution is due to the formation of Cu2O.

Carbohydrates are optically active polyhydroxy aldehydes and ketones or those compounds which on hydrolysis give such compounds are also carbohydrates. The carbohydrates which are not hydrolysed are called monosaccharides. Monosaccharides with aldehydic group are called Aldoses and those with free Ketonic group are called Ketoses. Carbohydrates are optically active. Number of optical isomers= 2 n , where n= number of asymmetric carbons. Carbohydrates are mainly synthesised by plants during photosynthesis. The monosaccharides exist in the form of cyclic structures. In cyclization, the -OH group combines with the aldehydic or ketonic group. As a result, cyclic structures of five or six membered rings containing one oxygen are formed e.g. Glucose, Fructose, Galactose. 

(xvi) What are carbohydrates? 

(xvii) What are Aldoses? 

(xviii) Define Monosaccharides. 

(xix) Name a monosaccharide. 

(xx) Glucose molecule has four asymmetric carbons. Find the total number of optical isomers in glucose.