21.

Affinity for hydrogen decreases in the group from fluorine to iodine. Which ofthe halogen acids should have highest bond dissociation enthalpy?

• HF

• HCl

• HBr

• HI

Excess fluoride (over 10 ppm) in drinking water can cause

• harmful effect of bones and teeth

• methemoglobinemia

• kidney damage

• laxative effect

KF has ccp structure. How many F^- ions and octahedral voids are there in this unit cell respectively?

• 4 and 4

• 4 and 8

• 8 and 4

• 6 and 6

A chelating agent has two or more than two donor atoms to bind a single metal ion. Which of the following is not a chelating agent?

• Thiosulphato

• Glycinato

• Oxalato

• Ethane-1, 2-diamine

On addition of small amount of KMnO₄ to conc. H₂SO₄, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following

• Mn₂O₇

• MnO₂

• MnSO₄

• Mn₂O₃

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magmetic moment

• 3d⁷

• 3d⁵

• 3d⁸

• 3d²

Which of the following statement is not correct about an inert electrode in a cell?

• It does not participate in the cell reaction.

• It provides surface either for oxidation or for reduction reaction.

• It provides surface for conduction of electrons.

• It provides surface for redox reaction

Which of the following statement is correct?

• E_cell and ${∆}_{\mathrm{f}}$G of cell reaction both are extensive properties.

• E_cell and ${∆}_{\mathrm{f}}\mathrm{G}$ of cell reaction both are intensive properties

• E_cell in the intensive property while ${∆}_{\mathrm{r}}\mathrm{G}$ of cell reaction is an extensive property

• E_cell is an extensive property while ${∆}_{\mathrm{r}}\mathrm{G}$ of cell reaction is an intensive property.

Which of the following curves is in accordance with Freundlich adsorption isotherm?

When Br₂ is treated with aqueous solutions of NaF, NaCl, NaI separately

• F₂, Cl₂ and I₂ are liberated

• only F₂ and Cl₂ are liberated

• only I₂ is liberated

• only Cl₂ is liberated