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
A.
3.73
Molarity (C) =
Molality (m) =
where, WB = mass of solute; MB = molar mass of solute; m = ?
MB = mass of CH3OH
= 32 (12 + 3 + 16 + 1)
WB(%) = = = 10.66 gm (%)
and m =
m = 3.728 ≈ 3.73 m
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 common features among CO, CN- and NO are
Bond order three and isoelectronic.
Bond order three and weak field ligands.
Bond order two and -acceptors.
Bond order three and -donors.
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