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%
C.
84%
Since, MgCO3 MgO + CO2
Mole ratio 1 : 1 : 1
Mass ratio 84 : 40 : 44
Given values 10 gm - 4 gm 0.1 mol = 4.4 g ()
(i) 84 gm of MgCO3 give MgO = 40 gm
10 gm of MgCO3 give MgO = = 4.76 gm
Thus, MgO obtained is less by = 4.76 - 4.0 = 0.76 gm
(ii) 84 gm of MgCO3 give CO2 = 44 gm
10 gm of MgCO3 give CO2 = = 5.23 gm
Thus, CO2 obtained is less by 5.23 - 4.4 = 0.84 gm
Total short = 0.76 + 0.84 = 1.59 ≅ 1.60
10 gm of MgCO3 give less products by = 1.60 gm
100 gm of MgCO3 give less products by = 1.600 gm
Hence, MgCO3 = 100 - 16 = 84%
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