1
IIT-JEE 1979
MCQ (Single Correct Answer)
+2
-0.5
The octet rule is not valid for the molecule
A
CO2
B
H2O
C
O2
D
CO
2
IIT-JEE 1979
Subjective
+3
-0

Account for the following : Limit your answer to two sentences.

"Atomic weights of most of the elements are fractional."

3
IIT-JEE 1979
Subjective
+4
-0

A white amorphous powder (A) on heating yields a colourless, non-combustible gas (B) and a solid (C). The latter compound assumes a yellow colour on heating and changes to white on cooling. (C) dissolves in dilute acid and the resulting solution gives a white precipitate on adding K4Fe(CN)6 solution.

(A) dissolves in dilute HCl with the evolution of gas, which is identical in all respects with (B). The gas (B) turns lime water milky, but the milkiness disappears with the continuous passage of gas. The solution of (A), as obtained above, gives a white precipitate (D) on the addition of excess of NH4OH and passing H2S. Another portion of the solution gives initially a white precipitate (E) on the addition of sodium hydroxide solution, which dissolves on further addition of the base. Identify the compounds (A), (B), (C), (D) and (E).

4
IIT-JEE 1979
Subjective
+2
-0
The precipitation of second group sulphides in qualitative analysis is carried out with hydrogen sulphide in the presence of hydrochloric acid but not in nitric acid. Explain.
JEE Advanced Papers
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12