At 90⁰C , pure water has [H⁺]=10^-6 M , if 100 mL of 0.2 M HCl is added to 200mL of 0.1 M KOH at 90°C then pH of the resulting solution will be:

• 5

• 6

• 7

• 4

A light greenish coloured salt was soluble in water. On passing H₂S into the solution a black precipitate was obtained which dissolved readily in HCl The metal ion present is:

• Co²⁺

• Fe²⁺

• Ni²⁺

• Mn²⁺

The E-isomer among the following is:

Arrange the following in the decreasing order of their melting points:
I. Heptane      II. Octane
III. Nonane     IV. Decane

• IV > II > III > I

• IV > III > I > II

• I > II > IV > III

• II > III > I > IV

Photochemical oxidants, i.e. PAN or PBN are formed by:

• action of nitrogen oxides on hydrocarbons in presence of sunlight

• action of CO₂ on hydrocarbons in presence of sunlight

• action of hydrogen sulphide on hydrocarbon in presence of sunlight

• None of the above

A salt on reacting with dil. H₂S0₄ gives a reddish brown gas. The salt is:

• KNO₂

• ZnBr₂

• NaNO₃

• FeCl₃

Which of the following reactions depicts the reducing action of H₂O₂ ?

• C₆H₆ + H₂O₂ $\to$ C₆H₅OH + H₂O

• 2I^- + 2H⁺ + H₂O₂ $\to$ I₂ + H₂O

• 2Mn${\mathrm{O}}_4^{-}$ + 6H⁺ +5H₂O₂ $\to$2Mn²⁺ + 5O₂ + 8H₂O

• PbS + 4H₂O₂ $\to$ PbSO₄ + 4H₂O

18.

Which of the following statements is correct with respect to the property of elements with increase in atomic number in the carbon family (group 14)?

• Their metallic character decreases

• The stability of +2 oxidation state increases

• Their ionization energy increases

• Their atomic size decreases

Aluminium vessels should not be washed with material containing washing soda since:

• washing soda is expensive

• washing soda is easily decomposed

• washing soda reacts with Al to form insoluble aluminium oxide

• washing soda reacts with Al to form soluble aluminate

Which of the following alkaline earth metal oxides shows a coordination number four?

• BeO

• MgO

• SrO

• CaO