[Y] May be prepared by which one of the following methods?
[A] By dehydration of malonic acid with
[B] By thermal decomposition of carbon sub-oxide in air.
[C] By heating potassium hyxacyaanoferrate (II) with conic
[D] By the action of conc. on charcoal
Select the correct statement about elements of group .
(A) The order of stability of oxidation state for +3 is and for +5 is
(B) In the case of nitrogen, all oxidation states from +1 to +4 tend to disproportionate in acid solution.
(C) There is considerable increase in covalent radius from N to P but from As to Bi only a small increase in covalent radius is observed.
(D) All of these.
A brown coloured mixture of two gases is obtained by the reduction of 6N nitric acid with metallic
copper. This mixture on cooling condenses to a blue liquid which on freezing (-30o C) gives a blue solid.
The correct choice for blue liquid or solid is.
(A) It is referred to as the anhydride of nitrous acid.
(B) It is an acidic oxide and hence dissolves in alkalies producing nitrites.
(C) It can also be prepared by the action of 50% HNO3 on arsenious oxide and then cooling to 250K.
(D) All of these.
Select the incorrect statement
(A) Nitrous oxide supports combustion more vigorously than air.
(B) Phosphorous pentaoxide dehydrates nitric acid forming nitrogen pentaoxide.
(C) Reactivity order of various allotropic forms of phosphorous is white > red > black.
(D) Red phosphorous changes to white phosphorus on heating in the atmosphere of or coal gas at 573 K.
Phosphate rock (fluorapatite) on reaction with orthophosphoric acid produces:
Which of the following orders is correct?
(1) – Boiling Point
(2) – Thermal Stability
(3) – Basic Character
(4) – Bond Angle
(A) (1), (2) and (3) only (B) (2), (3) and (4) only
(C) (1), (3) and (4) only (D) (1), (2), (3) and (4).
Which of the following is correct?
(A) – contains no S - S linkage.
(B) – contains – O - O linkage.
(C) – contains P – P linkage.
(D) - contains S – S linkage.
Concept Questions :-