Which is the most thermodynamically stable form of carbon?
Carbon black
Graphene
Graphite
Diamond
A gaseous carbon compound is soluble in dilute HCl. The solution on treating with NaNO2 gives off nitrogen leaving behind a solution which smells of wood spirit. The carbon compound is
HCHO
CO
C2H5NH2
CH3NH2
A signature, written in carbon pencil weighs 1 mg. What are the number of carbon atoms mpresent in the signature?
5.02 × 1023
5.02 × 1020
6.02 × 1020
0.502 × 1020
Activated charcoal is used to remove colouring matter from pure substances. It works by
oxidation
reduction
bleaching
adsorption
Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite
is an allotropic form of carbon
ia a non-crystalline substance
has carbon atoms arranged in large plates of ring of strongly bond carbon atoms with weak interplate bonds
has molecules of variable molecular masses like polymers
Which one of the following has maximum number of atoms of oxygen?
2 gm of carbon monoxide
2gm of carbon dioxide
2 gm of sulphur dioxide
2 gm of water
Carbon cannot reduce Fe2O3 to Fe at a temperature below 983 K because
free energy change for the formation of CO is more negative than that of Fe2O3
CO is thermodynamically more stable than Fe2O3
carbon has higher affinity towards oxygen than iron
iron has higher affinity towards oxygen than carbon