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 equivalents of CaCO₃ is: (molar mass of calcium bicarbonate is 162 g mol^-1 and magnesium bicarbonate is 146 g mol^-1)

• 1,000 ppm

• 100 ppm

• 10,000 ppm

• 5000 ppm

The correct order of hydration enthalpies of alkali metal ions is:

• Li⁺ > Na⁺ > K⁺ > Cs⁺ > Rb⁺

• Na⁺ > Li⁺ > K⁺ > Rb⁺ > Cs⁺

• Na⁺ > Li⁺ > K⁺ > Cs⁺ > Rb⁺

• Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺

Assertion : Ozone is destroyed by CFCs in the upper stratosphere.

Reason : Ozone holes increase the amount of UV radiation reaching the earth.

• Assertion and reason are incorrect.

• Assertion is false, but the reason is correct.

• Assertion and reason are correct and the reason is the correct explanation for the assertion.

• Assertion and reason are correct, but the reason is not the explanation for the assertion.

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

• Avoiding the use of floodlighted facilities

• Setting up compost tin in gardens

• Restricting the use of vehicles

• Using plastic bags

For the reaction 2A + B → C, the values of initial rate at different reactant concentrations are given in the table below. The rate law for the reaction is :

• Rate = k[A]²[B]²

• Rate = k[A]²[B]

• Rate = k[A][B]

• Rate = k[A][B]²

Given that,

 $$\begin{gathered} {\mathrm{E}}_{{\mathrm{O}}_2/ {\mathrm{H}}_2\mathrm{O}}^{⊝} = +1.23 \mathrm{V} \\ {\mathrm{E}}_{{\mathrm{S}}_2{\mathrm{O}}_8^{2-}/ {\mathrm{SO}}_4^{2-}}^{⊝} = 2.05 \mathrm{V} \\ {\mathrm{E}}_{{\mathrm{Br}}_2/ \mathrm{Br}}^{⊝} = +1.09 \mathrm{V} \\ {\mathrm{E}}_{{\mathrm{Au}}^{3+}/ \mathrm{Au}}^{⊝} = +1.4 \mathrm{V} \end{gathered}$$

The strongest oxidising agent is

• Br²⁺

• O₂

• Au³⁺

• S₂O${}_8^{2-}$

Adsorption of a gas follows Freundlich adsorption isotherm. x is the mass of the gas adsorbed on mass m of the adsorbent. The plot of log $\frac{x}{m}$ versus log p is shown in the given graph. $\frac{x}{m}$ is proportional to :

• p^3/2

• P³

• P²

• P^2/3

With respect to an ore, Ellingham diagram helps to predict the feasibility of its

• Thermal reduction

• Electrolysis

• Zone refining

• Vapour phase refining

The following ligand is

• tetradentate

• bidentate

• hexadentate

• tridentate

20.

Element ‘B’ forms ccp structure and ‘A’ occupies half of the octahedral voids, while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is:

• AB₂O₄

• A₂B₂O

• A₂BO₄

• A₄B₂O