10 g of a mixture of $C{u}_{2}S$ and CuS is reacted with 150 ml 1M $KMn{O}_4$ producing ${\mathrm{Cu}}^{2+},<mspace\; width="1em"></mspace>{\mathrm{Mn}}^{2+}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{SO}}_2$. The excess of $KMn{O}_4$ is completely reacted with 175 ml 1M $F{e}^{2+}$ in acidic medium. Percentage of CuS in hte mixture will be

1.  37%

2.  47%

3.  57%

4.  67%

In Haber processes, 30 L  of dihydrogen and 30L of dinitrogen were taken for the reaction which yielded only 50% of the expected product. What will be the composition of the gaseous mixture under the aforesaid conditions in the end?

1. 20L of ammonia, 25L of nitrogen, 15L of hydrogen

2. 20L of ammonia, 20L of nitrogen, 20L of hydrogen

3. 10L of ammonia, 25L of nitrogen, 15L of hydrogen

4. 20L of ammonia, 10L of nitrogen, 30L of hydrogen

25 ml of a mixture of NaOH and ${\mathrm{N}}_2{\mathrm{CO}}_3$ is titrated against N/10 HCI using phenolphthalin as an indicator then the volume of HCI used was 20 ml. Now, the same 25 ml of the same mixture is titrated against N/10 HCI using methyl orange indicator then the volume of HCI used was 25 ml. Weight of NaOH is the mixture will be

1. 0.02 gm

2. 0.04 gm

3. 0.06 gm

4. 0.08 gm

Dehydration of cyclohexanol yields cyclohexene in 75% yield. How much of cyclohexene will be obtained from 100g of cyclohexanol?

1. 75.0g

2. 61.5g

3. 82.0g

4. 41.0g

A metal nitride ${\mathrm{M}}_3<mspace\; width="1em"></mspace>{\mathrm{N}}_2$ contains 28% of nitrogen. The atomic mass of metal M is:

1. 24

2. 54

3. 9

4. 87.62

1.0 mol of Fe reacts completely with 0.65 mol of O₂ to give a mixture of only FeO and Fe₂O₃. The mole ratio of ferrous oxide to ferric oxide is

(1) 2 : 2

(2) 4 : 3

(3) 1 : 2

(4) 2 : 7

The percentage of copper in a copper(II) salt can be determined by using a thiosulphate titration. 0.305 gm of a copper(II) salt was dissolved in water and added to, an excess of potassium iodide solution liberating iodine according to the following equation 2Cu² (aq) + 4I^– (aq) $\stackrel{}{\rightleftharpoons }$ 2CuI(s) + I₂(aq) The iodine liberated required 24.5cm³ of a 0.100 mole dm^-3 solution of sodium thiosulphate 2S₂O₃^2- (aq) + I₂(aq) $\underset{}{\overset{}{\to }}$ 2I^– (aq) + S₄O₆^2- (aq) the percentage of copper, by mass in the copper(ll) salt is. [Atomic mass of copper = 63.5]

1. 64.2

2. 51.0

3 48.4

4. 25.5

Oxygen contains 90% O¹⁶ and 10% O¹⁸. Its atomic mass is

(1) 17.4

(2) 16.2

(3) 16.5

(4) 17

KClO₃ on heating decomposes to KCl and O₂. The volume of O₂ at STP liberated by 0.1 mole KClO₃ is

1. 4.36 L

2. 3.36 L

3. 2.36 L

4. None of these

At S.T.P. the density of CCl₄ vapour in g/L will be nearest to [CBSE PMT 1988]

(1) 6.84

(2) 3.42

(3) 10.26

(4) 4.57