Chemistry Test - 29

Nitric oxide is used as catalyst in lead chamber process.

The sublimation process is used for the separation of those solids which sublime on heating from non-volatile solids. The process is generally used for the purification of camphor, naphthalene anthracene, benzoic acid, etc. containing non-volatile impurities.

When a beam of light is passed through a colloidal solution, it gets scattered due to tyndall effect.

Valence shell electronic configuration of Co(27) = [Ar] 3d⁷, 4s²

Valence shell electronic configuration of Co³⁺(24) = [Ar] 3d⁶, 4s⁰

The number of unpaired electrons in the complex ion [CoF₆]^3- is 4.

Calcium cyanamide reacts with steam to form ammonia and calcium carbonate CaCN₂+3H₂O→ CaCO₃++2NH₃

Optical activity occurs in chiral (asymmetrical) molecules, because the mirror image is different from the original one, which is the course for the optical activity measured. 3-Methylheptane is an optically active compound.

Adenine and thymine form two hydrogen bonds.

To estimate the calcium content in the given solution, a known volume of it is titrated with standard EDTA solution. In the presence of magnesium, calcium can be titrated with EDTA by using Patton and Reeder's indicator at pH values between 12 and 14. The indicator combines with calcium ions forming a red coloured complex.

Near the end point, when free calcium ions are exhausted in the solution, further addition of EDTA dissociates Ca-In complex, consumes the calcium ions and releases free indicator, which is blue in colour. Therefore, the colour change is wine red to blue.

The carbonyl carbon being sp^2-hybridised has a planar arrangement of threeσ bonds and the nucleophile (here CN^-) can attack from both sides.

Hence, the product formed is a 50% - 50% mixture of both enantiomers i.e., a racemic mixture is obtained.

Therefore, 50% of molecules (lactic acid) will have the D-configuration and 50% will have the L-configuration.