Which of the following statements are correct?
(a)
centre of mass of a body always coincides with the centre of gravity of the body .
(b)
centre of gravity of a body is the point about which the total gravitational torque on the body is zero.
(c)
a couple on a body produce both translational and rotation motion in a body.
(d)
mechanical advantage greater than one means that small effort can be used to lift a large load.
1.
(a) and (b)
2.
(b) and (c)
3.
(c) and (d)
4.
(b) and (d)
The mechanism of a hypothetical reaction
X2 + Y2 → 2XY is given below:
(i) X2 → X + X (Fast)
(ii) X + Y2 ⇄ XY + Y (slow)
(iii) X + Y → XY (Fast)
The overall order of the reaction will be:
1. 2
2. 0
3. 1.5
4. 1
The element Z = 114 has been discovered recently. Family/group and electronic configuration from which it will belong are:
1. Carbon family and [Rn] 5f14 6d10 7s2 7p2
2. Oxygen family and [Rn] 5f14 6d10 7s2 7p4
3. Nitrogen family and [Rn] 5f14 6d10 7s2 7p6
4. Halogen family and [Rn] 5f14 6d10 7s2 7p5
The heating of phenylmethyl ether with HI produces-
1. Iodobenzene
2. Phenol
3. Benzene
4. Ethyl chloride
The correct order of acidity among the following is:
| 1. | \(\mathrm{CH \equiv CH > CH_3 - C \equiv CH }\) \(\mathrm{ > CH_2 = CH_2 > CH_3 - CH_3}\) |
| 2. | \(\mathrm{CH \equiv CH > CH_2 = CH_2 }\) \(\mathrm{ > CH_3 - C \equiv CH > CH_3 - CH_3}\) |
| 3. | \(\mathrm{CH_3 - CH_3 > CH_2 = CH_2 }\) \(\mathrm{ > CH_3 - C \equiv CH > CH \equiv CH }\) |
| 4. | \(\mathrm{ CH_2 = CH_2 > CH_3 - CH_3 }\) \(\mathrm{ > CH_3 - C \equiv CH > CH \equiv CH}\) |
1. \(A :\) \(H_{3} C - \underset{OH}{\underset{\left|\right.}{C}} = CH_{2}\) \(\) \(;\) \(B :\) \(\) \(H_{3} C - \underset{HSO_{4}}{\underset{\left|\right.}{C}} = CH_{2}\)
2. \(A :\) \(H_{3} C - \underset{O}{\underset{\left|\right. \left|\right.}{C}} - CH_{3}\) \(\) \(;\) \(B :\) \(\) \(H_{3} C - C \equiv CH\)
3. \(A :\) \(H_{3} C - \overset{OH}{\overset{\left|\right.}{C}} = CH_{2}\) \(\) \(;\) \(B :\) \(\) \(H_{3} C - \overset{O}{\overset{\left|\right. \left|\right.}{C}} - CH_{3}\)
4. \(A :\) \(H_{3} C - \underset{HS O_{4}}{\underset{\left|\right.}{C}} = CH_{2}\) \(\) \(;\) \(B :\) \(\) \(H_{3} C - \underset{O}{\underset{\left|\right. \left|\right.}{C}} - CH_{3}\)
The equilibrium of three reactions with their respective equilibrium constants are given below,
\( \begin{array}{lc} \mathrm{N}_2+3 \mathrm{H}_2 \rightleftharpoons 2 \mathrm{NH}_3 & \mathrm{~K}_1 \\ \mathrm{~N}_2+\mathrm{O}_2 \rightleftharpoons 2 \mathrm{NO} & \mathrm{K}_2 \\ \mathrm{H}_2+\frac{1}{2} \mathrm{O}_2 \rightleftharpoons \mathrm{H}_2 \mathrm{O} & \mathrm{K}_3 \end{array} \)
The equilibrium constant (K) of the following reaction will be :
1. \( \frac{K_{2}K_{3}^{3}}{K_{1}}\)
2. \( \frac{K_{2}K_{3}}{K_{1}}\)
3. \( \frac{K_{2}^{3}K_{3}}{K_{1}}\)
4. \( \frac{K_{3}^{3}K_{1}}{K_{2}}\)
Mark the correct increasing order of basic strength of given molecules:
 |
 |
 |
| (I) | (II) | (III) |
1. III < I < II
2. III < II < I
3. II < I < III
4. II < III < I
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