The molality of the 3M solution of methanol if the density of the solution is 0.9 g cm^-3 is

• 3.73

• 3.0

• 3.33

• 3.1

Consider a fuel cell supplied with 1 mol of H₂ gas and 10 moles of O₂ gas. If fuel cell is operated at 9.63 mA current, how long will it deliver power? (Assume 1 F = 96500 C/mole of electrons).

• 1 × 10⁶ s

• 0.5 × 10⁶ s

• 2 × 10⁶ s

• 4 × 10⁶ s

10 g of MgCO₃ decomposes on heating to 0.1 mole CO₂ and 4 g MgO. The percent purity of MgCO₃ is

• 24%

• 44%

• 84%

• 74%

The compound Na₂CO₃ . x H₂O has 50% H₂O by mass. The value of "x" is

• 4

• 5

• 6

• 8

Hybridisation of carbon is CH${}_3^{-}$

• sp²

• sp³

• sp³d

• sp³d²

The common features among CO, CN^- and NO${}_2^{+}$ are

• Bond order three and isoelectronic.

• Bond order three and weak field ligands.

• Bond order two and $\mathrm{\pi }$-acceptors.

• Bond order three and $\mathrm{\pi }$-donors.

Which of the following is covalent?

• NaCl

• KCl

• BeCl

• MgCl₂

The inert gas found most abundant in the atmosphere is

• He

• Ne

• Ar

• Kr

19.

Water gas is produced by

• Passing steam over red hot coke

• Passing steam and air over red hot.

• Burning coke is excess air.

• Burning coke is limited supply of air.

The volume of oxygen liberated at STP from 15 mL of 20 volume H₂O₂ is

• 100 mL

• 200 mL

• 300 mL

• 400 mL