Which one of the following statements about water is false?

• Water can act both as an acid and as a base.

• There is extensive intramolecular hydrogen bonding in the condensed phase.

• Ice formed by heavy water sinks in normal water.

• Ice formed by heavy water sinks in normal water.

The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to the high concentration of:

• Lead

• Nitrate

• Iron

• Iron

From the following statements regarding H₂O₂, choose the incorrect statement:

• It can act only as an oxidising agent

• It decomposed on exposure to light

• It has to be stored in plastic or wax lined glass bottles in dark

• It has to be stored in plastic or wax lined glass bottles in dark

In which of the following reactions H₂O₂ acts as a reducing agent?
I. H₂O₂ + 2H⁺ + 2e^- →2H₂O
II. H₂O₂ - 2e^- →O₂ + 2H⁺
III. H₂O₂ +2e^-→ 2OH^-
IV. H₂O₂+ 2OH^- -2e^- →O₂ + 2H₂O

• I and II

• III and IV

• I and III

• I and III

5.

Very pure hydrogen (99.9%) can be made by which of the following processes?

• Reaction of methane with steam

• Mixing natural hydrocarbons of high molecular weight

• Electrolysis of water

• Electrolysis of water

In context with the industrial preparation of hydrogen from water gas (CO + H₂), which of the following is the correct statement?

• CO and H2 are fractionally separated using differences in their densities

• CO is removed by absorption in aqueous Cu2Cl2 solution

• H₂ is removed through occlusion with Pd

• H₂ is removed through occlusion with Pd

Number of hydrogen ions present in 10 milionth part of 1.33 cm³ of pure water at 25°C is

• 6.023 million

• 60 million

• 8.01 million

• 80.23 million

Some statements about heavy water are given below.
(i) Heavy water is used as moderator in nuclear reactors.
(ii) Heavy water is more associated than ordinary water.
(iii) Heavy water is more effective solvent than ordinary water.
Which of the above statements are correct?

• (i) and (ii)

• (i), (ii) and (iii)

• (ii) and (iii)

• (i) and (iii)

The heat of formation of water is 260 kJ. How much H₂O is decomposed by 130 kJ of heat?

• 0.25 mol

• 1 mol

• 0.5 mol

• 2 mol

What is the quantity of hydrogen gas liberated when 46 g sodium reacts with excess ethanol? (Given atomic mass of Na = 23)

• 2.4 × 10^-3 kg

• 2.0 × 10^-3 kg

• 4.0 × 10^-3 kg

• 2.4 × 10^-2 kg