Which one of the following order is correct for the first ionisation energies of the elements?
B <Be <N < O
Be <B <N < O
B <Be <O <N
B <O <Be <N
The cubic unit cell of a metal (molar mass = 63.55 g mol-1) has an edge length of 362 pm. Its density is 8. 92 g cm-3. The type of unit cell is
primitive
face centred
body centred
end centred
The equilibrium constant for the given reaction is 100.
What is the equilibrium constant for the reaction given below?
10
1
0.1
0.01
20 mL of 0.1 M acetic acid is mixed with 50 mL of potassium acetate. Ka of acetic acid = 1.8 x 10-5 at 27C. Calculate concentration of potassium acetate if pH of the mixture is 4.8.
0.1 M
0.04 M
0.4 M
0.02 M
The chemical entities present in thermosphere of the atmosphere are
O3
A.
The thermosphere is the fourth layer of the earth's atmosphere and is located above the mesosphere. The air is thin in the thermosphere. The earth's thermosphere also includes the region of the atmosphere, called the ionosphere. The ionosphere is the region of the atmosphere that is filled with charged particles such as ,O+, NO+. The high temperature in the thermosphere can cause molecules to ionize.
Match the following.
List I | List II | ||
(A) | Flespar | (I) | [Ag3SbS3] |
(B) | Asbestos | (II) | Al2O3.H2O |
(C) | Pyrargyrite | (III) | MgSO4.H2O |
(D) | Diaspore | (IV) | KAlSi3O8 |
(V) | CaMg3(SiO3)4 |
(A) (B) (C) (D)
IV V II I
(A) (B) (C) (D)
IV V I II
(A) (B) (C) (D)
IV I III II
(A) (B) (C) (D)
II V IV I
The concentration of an organic compound in chloroform is 6.15 g per 100 mL of solution. A portion of this solution in a 5 cm polarimeter tube causes an observed rotation of -1.2°. What is the specific rotation of the compound?
+12
-3.9
-39
+61.5
Fluorine reacts with dilute NaOH and forms a gaseous. product A. The bond angle in the molecule of A is
104°40'
103°
107°
109°28'