The standard enthalpies of formation of A(NH₃), B(CO₂), C(HI) and D(SO₂) are - 46.19, -393.4, +24.94 and -296.9 kJ mol1 respectively. The increasing order of their
stability is 

• B < D < A < C

• C < A < D < B

• D < B < C < A

• A < C < D < B

Which of the following pair of metals is purified by van- Arkel method?

• Zr and Ti

• Ag and Au

• Ni and Fe

• Ga and In

In Fischer-Ringe's method of separation of nobles gas mixture from air, ......... is used

• 90% CaC₂ + 10% CaCl₂

• coconut charcol

• soda lime + potash solution

• 90% CaCO₃ + 10% urea

In Duma's method of estimation of nitrogen, 0.35 g of an organic compound gave 55 mL of nitrogen collected at 300 K temperature and 715 mm pressure. The percentage composition of nitrogen in the compound would be (Aqueous tension at 300 K = 15 mm)

• 16.45

• 17.45

• 14.45

• 15.45

15.

Which of the following is not correct?

• Ammonia is used as refrigerant

• A mixture of Ca(CN)₂ and C is known as nitrolim

• A mixture of Ca(H₂PO₄),% and CaSO₄.2H₂0 is known as superphosphate of lime

• Hydrolysis of NCl₃ gives NH₃ and HOCl

Which one of the following is aromatic?

• Cyclopentadienyl cation

• Cyclooctatetraene

• Cycloheptatriene

• Cycloheptatrienylcation

The complexes [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆] are the examples of which type of isomerism?

• Ionisation isomerism

• Coordination isomerism

• Geometrical isomerism

• Linkage isomerism

Which of the following compounds is soluble in benzene but almost insoluble in water?

• C₂H₅OH

• CH₃CO₂H

• CH₃CHO

• C₆H₅NO₂

Which one of the following reactions does not form gaseous product?

• PbO₂ + H₂O₂ $\to$

• Acidified KMnO₄ + H₂O₂ $\to$

• PbS + H₂O₂ $\to$

• Cl₂ + H₂O₂ $\to$

Which of the following compounds has the lowest melting point?

• CaBr₂

• Cal₂

• CaF₂

• CaCl₂