Chemistry: Topic-wise Test- 5 - NEET MCQ

It is strictly covalent does not shows cationic & anionic form.

Pseudo halides are
CN^–, NC^–, OCN^–, SCN^–, SeCN^–
NCS^–, N₃^–, NCO^–

(NH₄)₂Cr₂O₇ → Cr₂O₃ + H₂O + N₂

Dissolved NO₂ makes it yellow

NaBH₄ brings about reduction of carbonyls by hydrid e transfer mechanism at planar sp² carbon. Hence, if a chiral carbon is generated, racemic mixture is always produced.

In the above reaction, four stereoisomers, two pairs of enantiomers are formed. Each member of a pair of enantiomer is diastereomer of each member of other pair of enantiomer. Hence, fractional crystallisation would give two fractions, each containing racemic mixture.

Wolff-Kishner reduction is suitable for reduction of carbonyls containing olefinic bonds. If Clemmensen reduction is done, HCI also attacks olefinic bonds.

In acid catalysed aldo! condensation, enol acts as a nucleophile.

Dianion is better hydride donor. Also the electron donating group (CH₃O) increases hydride (H^-) donating a bility .

Unsymmetrical carbonyls give more than one oximes with hydroxylamine, hence more than one amides in the subsequent Beckmann rearrangement.

Symmetrical oximes give single amide in Beckmann rearrangement.

In BV oxidation, tertiary alkyl group has greater migrating aptitude than primary and secondary alkyl group.

Free radical coupling reaction of aldehydes and ketones.

This reaction involves the treatment of a methyl ketone (CH₃COCH₃) with nitrous acid (HNO₂) in the presence of ethyl nitrite (C₂H₅ONO) and HCl.

This is a Nef reaction, which converts a methyl ketone into an oxime derivative in the presence of nitrous acid. The mechanism involves the formation of an intermediate diazonium salt, followed by its rearrangement and hydrolysis, leading to the formation of an oxime.

Let's break down the product options:

• Option 1: This structure shows an imine with a hydroxyl group attached directly to nitrogen. However, this is not the expected structure from a Nef reaction.

• Option 2: This shows an oxime (CH₃COCH=NOH), which is the expected major product of the reaction.

• Option 3: This shows an ester-like product (CH₃COCH=NOEt), which is not the expected result of the Nef reaction.

• Option 4: This shows an imine derivative (CH₃COCH=NH), which is not the expected major product in this case.

Conclusion:

The major product of the reaction is the oxime, as shown in Option 2.

The correct answer is:

Option 2.

If blood glucose levels become too low, glucagon (pancreatic hormone) is released, which causes the liver to convert the stored glycogen back into glucose, and release it into the bloodstream.

• Sucrose (cane sugar) is a disaccharide: This means it is composed of two monosaccharides bonded together.


• Hydrolysis of sucrose: When sucrose is hydrolyzed, it breaks down into its two monosaccharide components.


• Components of sucrose: Sucrose is made up of one molecule of glucose and one molecule of fructose.


• Result of hydrolysis: Therefore, when sucrose is hydrolyzed, it gives one molecule of glucose and one molecule of fructose.

In α-helix, hydrogen bonds are present between –NH group of one amino acid residue to the >C= O group of another aminoacid residue.

Maltose can be produced from starch by hydrolysis in the presence of the enzyme diastase. It can be broken down into two glucose molecules by hydrolysis. In living organisms, the enzyme maltase can achieve this very rapidly. In the laboratory, heating with a strong acid for several minutes will produce the same result.

Sucrose or cane sugar is the commonest of the disaccharides. It has the molecular formula C₁₂H₂₂O₁₁. It does not form a phenylhydrazone or exhibit carbonyl properties. On hydrolysis with dilute acids, it yields one molecule of D-(+)-glucose and one molecule of D-(—)-fructose. It is not a reducing sugar. 

Glucose and fructose are functional isomers of each other Because they have same molecular formula that is C₆H₁₂O₆ But different functional group in their chemical formula. Glucose has aldehyde group while fructose has ketone as functional group.

Lactose: The sugar found naturally in milk, it is a disaccharide composed of one galactose unit and one glucose unit; sometimes called milk sugar.

Biuret solution is used to identify the presence of protein. Biuret reagent is a blue solution that, when it reacts with protein, will change color to pink-purple.

The correct answer is option D
α helix is one of the most common ways in which a polypeptide chain forms all possible hydrogen bonds (intermolecular and intramolecular hydrogen bond) by twisting into a right-handed screw(helix) with the N−H group of each amino acid residue hydrogen bonded to C=O of an adjacent turn of the helix.
 

The correct answer is A
Haemoglobin is a Quaternary protein because it has 4 polypeptide structures - 2alpha and 2 beta.

The correct sentence is option C
Since the half-life period is independent of the changing pressure, the reaction is of the first order.
The integrated rate law is (P_N2​O5​​)_t​=(P​^o_N2​O5​)₀​^e−kt
Thus the partial pressure of N₂​O_5​ decreases exponentially with time and the partial pressure of NO₂​ increases exponentially with time.
Hence, the correct graph is represented by option C.
 

(B) As only A is optically active. So conc. of A at t =20min ∝ 30° 

While concentration of A at t= 50min ∝ mc 15° 

So conc. has deceased to half oils value in 30 min, so t_1/2=30 min.

So volume consumed of H₂0₂ at t =30 min =t_1/2 ,is according to 50% production of B at t= 90 min. production of B=87.5%(Threehalflives)

So volume consumed =