Which statement is not correct about fullerene C60 ?
It contains 20 six membered rings and 12 five membered rings
All carbon atoms undergo sp2 hybridisation
A six membered ring is fused with six membered rings only
A five membered ring is fused with six membered ring only
Which is the most stable allotrope of sulphur?
Octahedral sulphur
Monoclinic sulphur
Plastic sulphur
Colloidal sulphur
A.
Octahedral sulphur
Octahedral sulphur (rhombic or α-sulphur) is the most stable allotrope of sulphur. It is stable at temperature below 95.6°C. Its specific gravity is 2.06. It melts at 114°C. It is soluble in carbon disulphide. Its crystal structure contains cyclic S8 rings packed in a manner which leads to the formation of rhombic crystals.
Select the most appropriate statement In BF3.
All the bonds are completely ionic.
All the bonds are covalent.
The B-F bond is partially ionic.
B-F bond has partial double bond character.
The correct formula of borax is
Na2[B4O4(OH)3].9H2O
Na2[B4O5(OH)4].8H2O
Na2[B4O6(OH)5].7H2O
Na2[B4O7(OH)6].6H2O
Which carbon is more electronegative ?
sp3 - hybridised carbon
sp - hybridised carbon
sp2 - hybridised carbon
Always same irrespective of its hybrid state