For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, U and w correspond to
U < 0, w = 0
U < 0, w < 0
U > 0, w = 0
U > 0, w > 0
A.
U < 0, w = 0
Bomb calorimeter commonly used to find the heat of combustion of organic substances, consists of a sealed combustion chamber, called a bomb.
The reaction in a bomb calorimeter proceeds at constant volume so, w = 0 and U = q.
Hence, U < 0, w = 0
How many significant figures are present in 0.0000135?
7
8
4
3
D.
3
Significant numbers in 0.0000135 are 3. It is because zeros to the left of the first non-zero digitin a number are not significant.
One mole of SO3 was placed in a vessel of 1 L capacity at a certain temperature and the following equilibrium was established.
2SO3 (g) 2SO2 (g) + O2 (g)
If 0.6 moles of SO2 were formed at equilibrium, Kc for the reaction will be
0.036
0.45
0.54
0.675
D.
0.675
Kc =
-particles can be detected by using
thin aluminium sheet
barium sulphate
zinc sulphide screen
gold foil
C.
zinc sulphide screen
particles can be detected by using zinc sulphide screen. It emits a flash of light upon -particle. It was first used by Rutherford.
The pair of amphoteric hydroxides is
Be(OH)2, Al(OH)3
Al(OH)3, LiOH
B(OH)3, Be(OH)2
Be(OH)2, Mg(OH)2
A.
Be(OH)2, Al(OH)3
Al and Be show similar properties due to their diagonal relationship.
In a decay process changes into . Which process is this?
-decay
decay
- decay
- decay.
B.
decay
In a decay process, when changes into , the process is known as decay. It can be explained as-
Assertion : Molecular nitrogen is less reactive than molecular oxygen.
Reason: The bond length of N2 is shorter than that of oxygen.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
A.
If both assertion and reason are true and reason is the correct explanation of assertion.
Bond order of N2 = 3, bond order of O2 = 2. Higher the bond order, shorter is the bond length and higher is the bond dissociation energy, i.e., higher stability or lesser reactivity. Thus, N2 is less reactive than O2.
The amount of BaSO4 precipitated on mixing BaCl2 (0.5 M) with H2SO4 (1 M) will correspond to
0.5 M
1.0 M
1.5 M
2.0 M
A.
0.5 M
[Ba2+] = 0.5 mol L-1
[S] = 1mol L-1
Ba2+ (aq) + S (aq) BaSO4 (s)
0.5 mol of Ba2+ would react with 0.5 mol of S ions to form 0.5 mol of BaSO4.
Which of the following arrangement is possible?
n | l | m | s |
5 | 2 | 2 | +1/2 |
2 | 2 | 0 | -1/2 |
3 | -2 | 1 | +1/2 |
0 | 0 | 1 | +1/2 |
A.
n | l | m | s |
5 | 2 | 2 | +1/2 |
For a given value of n, l = 0 to n - 1;
For a given value of l, m = -l to +l including zero;
For a given value of m, s =
Therefore, when n = 5, then l = 0, 1, 2, 3, 4;
when l = 2, then m = -2, -1, 0, +1, +2
The value of s can be
Hence, the arrangement, n = 5, l = 2, m = 2, s = + is possible for an electron.
Assertion : NF3 is a weaker ligand than N(CH3)3.
Reason : NF3 ionizes to give F- ions in aqueous solution.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
C.
If assertion is true but reason is false.
Due to high electronegativity and electron withdrawing nature of F-atom, the lone pair of N-atom in NF3 molecule is not easily available for donation. However, in N(CH3)3, -CH3 group is an electron releasing group, thus lone pair of N-atom in N(CH3)3 molecule can be ligated easily. Except for nitrogen fluoride, all other trihalides hydrolyse in water.
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