Noble gases are used in discharge tubes to give different colours. Reddish-orange glow is due to

• Ar

• Ne

• Xe

• Kr

52.

T-shaped inter halogen compound is:

• ClF₃

• ICl

• ClF₅

• IF₅

The correct order of acid strength is

• HClO < HClO₂ < HClO₃ < HClO₄

• HClO₄ < HClO < HClO₂ < HClO₃

• HClO₂ < HClO₃ < HClO₄ < HClO

• HClO₄ < HClO₃ < HClO₂ < HClO

Which of the following molecules forms no inter molecular hydrogen bonds?

• ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$

• HF

• ${\mathrm{CH}}_3{\mathrm{COCH}}_3$

• ${\mathrm{CH}}_3\mathrm{COOH}$

Which of the following metals, Fe, Zn, Pb, Ag and Pt do not give a metal nitrate on treatment with concentrated HNO?

• Fe and Zn.

• Fe and Pt.

• Pb, Ag and pt.

• Fe, Ag and Zn.

The oxidation number of sulphur atoms in peroxomonosulphuric acid H₂SO₅ and peroxodisulphuric acid H₂S₂O₈, respectively are:

• +8 and +7

• +6 and +6

• +4 and +6

• +3 and +3

When aqueous ammonia is added to green solution of nickel chloride, the colour changes to:

• yellow

• purple

• violet

• violet

Organophosphorus compounds are the most toxic insecticides. The common organophosphorus insecticides is:

• Methoxy chlor

• Dieldrin

• Parathion

• Malathion

In trimeta-phosphate ion, the number of 0 atom P-O-P bonds and unit negative charges are respectively:

• 6,6,3

• 3,6,3

• 9,3,3

• 9,6,3

Which of the following is the laboratory method for synthesis of nitric oxide?

• Reaction of zinc with cold and dilute HNO₃

• Reaction of zinc with concentrated HNO₃

• Reaction of copper with cold and dilute HNO₃

• Heating NH₄NO₃