JEE Main entrance exam Question Bank Solutions

Permanent hardness in water cannot be cured by ______.

Match List - I with List - II.

Choose the correct answer from the options given below:

Kjeldahl's method was used for the estimation of nitrogen in an organic compound. The ammonia evolved from 0.55 g of the compound neutralised 12.5 mL of 1 MH₂SO₄ solution. The percentage of nitrogen in the compound is ______. (Nearest integer)

A sample of 0.125 g of an organic compound when analyzed by Duma's method yields 22. 78 mL of nitrogen gas collected over KOH solution at 280 K and 759 mm Hg. The perentage of nitrogen in the given organic compound is ______. (Nearest integer)

Given:

1. The vapour pressure of water of 280 K is 14.2 mm Hg.
2. R = 0.082  L atm K^-1 mol^-1 

The transformation occurring in Duma's method is given below:

\[\ce{C2H7N + (2x + \frac{y}{2}) CuO -> xCO2 + \frac{y}{2} H2O + \frac{z}{2} N2 + (2x + \frac{y}{2}) Cu}\]

The value of y is ______. (Integer answer)

17.0 g of NH₃ completely vapourises at –33.42°C and 1 bar pressure and the enthalpy change in the process is 23.4 kJ mol^–1. The enthalpy change for the vapourisation of 85 g of NH₃ under the same conditions is ______ kJ.

According to the valence bond theory, the hybridization of central metal atom is dsp² for which one of the following compounds?

Which of the following reagent is used for the following reaction?

\[\ce{CH3CH2CH3 ->[?] CH3CH2CHO}\]

Number of amphoteric compounds among the following is:

BeO, BaO, Be(OH)₂, Sr(OH)₂

At 20°C, the vapour pressure of benzene is 70 torr and that of methyl benzene is 20 torr. The mole fraction of benzene in the vapour phase at 20°C above an equimolar mixture of benzene and methylbenzene is ______ × 10^-2. (Nearest integer)

The major product formed in the following reactions is:

Which one of the following methods is most suitable for preparing deionized water?

In carius method of estimation of halogen 0.172 g of an organic compound showed presence of 0.08 g of bromine. Which of these is the correct structure of the compound?

Select schemes A, B, C out of

(I) acid catalysed hydration

(II) HBO

(III) oxymercuration-demercuration

What would be the main product when propene reacts with HBr?

The most stable free radical among the following is:

100 ml of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalent of CaCO₃ is ______.

[Molar mass of calcium bicarbonate is 162 g mol^-1 and magnesium bicarbonate is 146 g mol^-1)

The enthalpy change states for the following processes are listed below:

\[\ce{Cl2(g) = 2Cl (g)}\]     242.3 kJ mol^-1

\[\ce{I2(g) = 2I(g)}\]     151 kJ mol^-1

\[\ce{ICI (g) = I(g) + Cl(g)}\]   242.3 kJ mol^-1

\[\ce{I2(s) = I2(g)}\]   62.76 kJ mol^-1

Given that the standard states for iodine chlorine are I₂ (s) and Cl₂ (g), the standard enthalpy of formation for ICl (g) is:

Propene, \[\ce{CH3 - CH = CH2}\] can be converted to 1-propanol by oxidation. Which set of reagents among the following is ideal to effect the conversion ______.

The destruction of the biological nature and activity of proteins by heat or chemical agent is called ______.