JEE Basic Concepts in Chemistry PYQs With Video Solutions PDF

The processes of calcination and roasting in metallurgical industries, respectively, can lead to:

A transition metal $$M$$ forms a volatile chloride which has a vapour density of 94.8. If it contains 74.75% of chlorine the formula of the metal chloride will be

'$$a$$' and '$$b$$' are van der Waals' constants for gases. Chlorine is more easily liquefied than ethane because:

The hardness of a water sample containing $$10^{-3}$$ M $$MgSO_4$$ expressed as $$CaCO_3$$ equivalents (in ppm) is ___________.
(molar mass of $$MgSO_4$$ is 120.37 g/mol)

A sample of CaCO$$_3$$ and MgCO$$_3$$ weighed 2.21 g is ignited to constant weight of 1.152 g. The composition of the mixture is: (Given molar mass in g mol$$^{-1}$$, CaCO$$_3$$: 100, MgCO$$_3$$: 84)

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Heavy water is used for the study of reaction mechanism.
Reason (R): The rate of reaction for the cleavage of O-H bond is slower than that of O-D bond.
Choose the most appropriate answer from the options given below:

Which of the following is a set of greenhouse gases?

An aqueous solution of a commercially available acid has a density of $$1.25\text{ g mL}^{-1}$$ and is labeled as $$36.5\%$$ by mass of $$\text{HCl}$$. Calculate the molality (m) and molarity (M) of this $$\text{HCl}$$ solution respectively.
(Take molar mass of $$\text{HCl} = 36.5\text{ g mol}^{-1})$$

A metal M crystallizes into two lattices :- face centred cubic (fcc) and body centred cubic (bcc) with unit cell edge length of $$2.0$$ and $$2.5$$ Å respectively. The ratio of densities of lattices fcc to bcc for the metal M is ______ (Nearest integer)

The primary pollutant that leads to photochemical smog is:

Excess of NaOH (aq) was added to 100 mL of FeCl$$_3$$ (aq) resulting into 2.14 g of Fe(OH)$$_3$$. The molarity of FeCl$$_3$$(aq) is: (Given the molar mass of Fe = 56 g mol$$^{-1}$$ and molar mass of Cl = 35.5 g mol$$^{-1}$$)

Identify the pollutant gases largely responsible for the discoloured and lustreless nature of marble of the Taj Mahal.

At 300 K, the density of a certain gaseous molecule at 2 bar is double to that of dinitrogen (N$$_2$$) at 4 bar. The molar mass of the gaseous molecule is

The molecular formula of a commercial resin used for exchanging ions in water softening is $$C_8H_7SO_3Na$$ (molecular weight = 206). What would be the maximum uptake of $$Ca^{2+}$$ ions by the resin if expressed in mol per gm?

The higher concentration of which gas in air can cause stiffness of flower buds?

Taj Mahal is being slowly disfigured and discoloured. This is primarily due to

Among $$10^{-9}$$ g (each) of the following elements, which one will have the highest number of atoms?
Element : Pb, Po, Pr and Pt

The molecule that has minimum or no role in the formation of photochemical smog, is:

Match Column I with Column II
Column I      Column II
A. Soda ash      I. CaSO$$_4$$
B. Chlorophyll      II. CaOH$$_2$$
C. Used in Whitewashing      III. Na$$_2$$CO$$_3$$
D. Dentistry, ornamental work      IV. Mg$$^{2+}$$ ions

0.27 g of a long chain fatty acid was dissolved in 100 cm$$^3$$ of hexane. 10 mL of this solution was added dropwise to the surface of water in a round watch glass. Hexane evaporates and a monolayer is formed. The distance from edge to centre of the watch glass is 10 cm. What is the height of the monolayer?
[Density of fatty acid = 0.9 g cm$$^{-3}$$; $$\pi = 3$$]

Which is wrong with respect to our responsibility as a human being to protect our environment?

Biochemical Oxygen Demand (BOD) is the amount of oxygen required (in ppm):

The elemental composition of a compound is  $$54.2\%C,\ 9.2\%H$$  and  $$36.6\%O.$$ If the molar mass of the compound is  $$132\ \text{g mol}^{-1},$$ the molecular formula of the compound is: [Given: Relative atomic masses  C:H:O = 12:1:16]

For per gram of reactant, the maximum quantity of N$$_2$$ gas is produced in which of the following thermal decomposition reactions? (Given: Atomic wt. : Cr = 52u, Ba = 137u)

A sample of NaClO$$_3$$ is converted by heat to NaCl with a loss of 0.16 g of oxygen. The residue is dissolved in water and precipitated as AgCl. The mass of AgCl (in g) obtained will be: (Given: Molar mass of AgCl = 143.5 g mol$$^{-1}$$)

NaClO$$_3$$ is used, even in spacecrafts, to produce O$$_2$$. The daily consumption of pure O$$_2$$ by a person in 492 L at 1 atm, 300K. How much amount of NaClO$$_3$$, in grams, is required to produce O$$_2$$ for the daily consumption of a person at 1 atm, 300K?
NaClO$$_3$$(s) + Fe(s) $$\rightarrow$$ O$$_2$$(g) + NaCl(s) + FeO(s)
R = 0.082 L atm mol$$^{-1}$$ K$$^{-1}$$

The correct statements among (a) to (d) regarding $$H_2$$ as a fuel are: (i) It produces less pollutants than petrol. (ii) A cylinder of compressed dihydrogen weighs ~ 30 times more than a petrol tank producing the same amount of energy. (iii) Dihydrogen is stored in tanks of metal alloys like $$NaNi_5$$. (iv) On combustion, values of energy released per gram of liquid dihydrogen and LPG are 50 and 142 kJ, respectively.

At 300 K and 1 atmospheric pressure, 10 mL of a hydrocarbon required 55 mL of O$$_2$$ for complete combustion, and 40 mL of CO$$_2$$ is formed. The formula of the hydrocarbon is:

Water samples with BOD values of 4 ppm and 18 ppm, respectively, are:

A 100 mL solution was made by adding 1.43 g of $$Na_2CO_3 \cdot xH_2O$$. The normality of the solution is 0.1 N. The value of x is __________ (The atomic mass of Na is 23 g/mol)