21.

When excess of NaOH solution is added to aqueous solution of iodine, the colour of solution becomes

• blue

• yellow

• colourless

• pale green

Which of the following statements is incorrect regarding the reaction?

CH₃CHO + [Ag(NH₃)₂]^$\oplus$ + OH^- _$\to$CH₃COO^- + Ag

• The equivalent weight of CH₃CHO is 22

• Three moles of OH^- are required in the above D reaction

• CH₃CHO is an oxidising agent

• Reduction of [Ag(NH₃)₂]^$\oplus$ occurs

In the reaction,

How many electron donating groups are attached with the carbon atom of unsaturated part of the product 'B' ?

• Two

• Three

• Four

• None of these

The magnitude of screening effect depends upon the number of

• inner electrons

• outer electrons

• bond order

• Both (a) and (b)

Duma's method involves the determination of nitrogen content in the organic compound in the form of

• NH₃

• N₂

• NaCN

• (NH₄)₂SO₄

Which of the following statement(s) is not correct?

• Suspended particulate matter is an important pollutant released by diesel vehicles

• Soot particles (size < 5$\mathrm{\mu }$) cause fibrosis of the lung living

• H₂SO₄ particulates have size of 500- 1000 nm

• Photochemical smog is formed by oxides of sulphur, smoke and dust particles

The value of n in

Mn${\mathrm{O}}_4^{-}$ + 8H⁺ + ne^- $\to$ Mn²⁺ + 4H₂O is

• 5

• 4

• 2

• 3

Solid NaHCO₃ will be neutralised by 40.0 mL of 0.1 M H₂SO₄ solution. What would be the weight of solid NaHCO₃ in gram?

• 0.672 g

• 6.07 g

• 17 g

• 20 g

For the cell reaction,

Pb + Sn²⁺ $\to$  Pb²⁺ + Sn

Given that, Pb $\to$ Pb²⁺, E$°$ = 0.13 V

Sn²⁺ +2e^- $\to$ Sn, E^$°$ = -0.14 V

What would be the ratio of cation concentration for which E = 0 ?

• $\frac{1}{4}$

• $\frac{1}{2}$

• $\frac{1}{3}$

• $\frac{1}{1}$

[CuCl₄]^2- exists while [CuI₄]^2- does not exist, because

• I^- is stronger reductant than Cl^-

• I^- is weaker reductant than Cl^-

• I^- is stronger oxidant than Cl^-

• None of the above