Chemistry Test - 18

For alkenes other then ethene, addition follows Markowinkov`s rule.

A nitro (- NO2) group can be reduced to the corresponding amino (- NH2) group by treatment with a reducing metal such as tin or zinc in the presence of acid. Sodium bicarbonate is used to neutralize the acid from the first step. This two-step sequence is an important route to aniline.

The diamond burns in air at 900 °C to give CO2.

Organic compounds in a mixture can be separated best by chromatography. It is the collective term for a set of laboratory techniques for the separation of mixtures. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to separate. The separation is based on differential partitioning between the mobile and stationary phases. Subtle differences in a compound's partition coefficient result in differential retention on the stationary phase and thus, change the separation.

Carnallite is an evaporite mineral, a hydrated potassium magnesium chloride with formula: KMgCl₃·6(H₂O).

The term inert pair effect is often used in relation to the increasing stability of oxidation states that are 2 less than the group valency for the heavier elements of groups 13, 14, 15 and 16. It is not a characteristic of the actinide series of elements.

thyne is oxidised by a dilute aqueous solution of potassium permanganate to form oxalic acid. Thus, if ethyne is bubbled through a solution of potassium permanganate, the solution is decolourised. This is Baeyer's test for unsaturated organic compounds.

Ethyne ==> Oxalic Acid (in presence of KMnO₄)

n order for PCl₅ to be formed, there must be five bonds, and to form five bonds, phosphorus must have five unpaired valence electrons. Phosphorus and nitrogen both have five valence electrons.

In order to have five unpaired electrons in P, we can imagine an electron being promoted from the 3s to the 3d sub-level. This will give 5 unpaired electrons, and the ability to form PCl₅. We can also relate this to the use of the d orbitals in phosphorus with sp³d hybridisation.

But for nitrogen, there are no 2d orbitals to promote a 2s electron into and no way to come up with five unpaired electrons. Therefore, NCl₅ does not exist.

Development of a photographic plate involves the use of a reducing agent.