Biomolecules — Chemistry STD 12 Science — Question

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

1. Assertion: Except glycine, all naturally occurring CL-amino acids are optically active.

Reason: All naturally occurring CL-amino acids, except glycine, has at least one asymmetric carbon.

2. Assertion: All amino acids are optically active.

Reason: Amino acids contain asymmetric carbon atoms.

3. Assertion: In $\alpha$-helix structure, intramolecular H-bonding takes place whereas in $\beta$-pleated structure, intermolecular H-bonding takes place.

Reason: An egg contains a soluble globular protein called albumin which is present in the white part.

4. Assertion: Secondary structure of protein refers to regular folding patterns of continuos portions of the polypeptide chain.

Reason: Out of 20 amino acids, only 12 amino acids can be synthesised by human body.

5. Assertion: The helical structure of protein is stabilised by intramolecular hydrogen bond between -NH and carbonyl oxygen.

Reason: Sanger's reagent is used for the identification of N-tenninal amino acid of peptide chain.

1. What is the oxidation state of metal in [Mn₂(CO)₁₀]?

1. +1
2. -1
3. +2
4. 0

2. Among the following metal carbonyls, the C-O bond order is lowest in:

1. [Mn(CO)₆]⁺
2. [Fe(CO)₅]
3. [Cr(CO)₆]
4. [V(CO)₆]^-

3. Which of the following can be reduced easily?

1. V(CO)₆
2. Mo(CO)₆
3. [Co(CO)₄]^-
4. Fe(CO)₅

4. The oxidation state of cobalt in K[Co(CO)₄] is:

1. +1
2. +3
3. -1
4. 0

5. Structure of decacarbonyl manganese is:

1. Trigonal bipyramidial
2. Octahedral
3. Tetrahedral
4. Square pyramidal

1. The rate constant for the reaction is:

1. 0.4s^-1
2. 0.02s^-1
3. 0.01s^-1
4. 0.3s^-1

2. The pressure of the gas A after 230 s will be:

1. 0.04 atm
2. 0.36 atm
3. 0.4 atm
4. 0.036 atm

3. The total pressure of the system after 230 swill be:

1. 2.15 atm
2. 1.12 atm
3. 0.4 atm
4. 3.08 atm

4. The plot ofln[A] vs twill be:

1. Linear with slope = k
2. Linear with intercept = In[A]₀
3. Linear with slope = In[A]₀
4. Linear with intercept = [A]₀

5. Which of the following is not an example of first order reaction?

1. $\text{C}_2\text{H}_{4(\text{g})}+\text{H}_{2(\text{g})}\rightarrow\text{C}_2\text{H}_{6(\text{g})}$
   
2. $2\text{N}_2\text{O}_{5(\text{g})}\rightarrow4\text{NO}_{2(\text{g})}+\text{O}_{2(\text{g})}$
   
3. $2\text{N}\text{H}_{3(\text{g})}\xrightarrow[\triangle]{\text{pt}}\text{N}_{2(\text{g})}+3\text{H}_{2(\text{g})}$
   
4. $2\text{N}_2\text{O}_{(\text{g})}\xrightarrow{\ \ \triangle\ \ }2\text{N}_{2(\text{g})}+\text{O}_{2(\text{g})}$
   

1. Among the following the most reactive towards alcoholic KOH is:

1. CH₂ = CHBr
2. CH₃COCH₂CH₂Br
3. CH₃CH2Br
4. CH₃CH₂CH₂Br

2. The general reaction, $\text{R}-\text{X}\xrightarrow{\text{aq.OH}^-}\text{ROH}+\text{X}^-,$ is expected to follow decreasing order of reactivity as in:

1. t-BuI> t-BuBr > t-BuCI > t-BuF
2. t-BuF > t-BuCI > t-BuBr > t-BuI
3. t-BuBr > t-BuCI >t-BuI> t-BuF
4. t-BuF > t-BuCI > t-BuI > t-BuBr

3. Reaction of t-butyl bromide with sodium methoxide produces:

1. Sodium t-butoxide.
2. t-butyl methyl ether.
3. Iso-butane.
4. Iso-butylene.

4. In the elimination reactions, the reactivity of alkyl halides follows the sequence:

1. R - F > R - CI > R - Br > R - I
2. R - I > R - Br > R - Cl > R - F
3. R - I > R - F > R - Br > R - CI
4. R - F > R - I > R - Br > R - CI

5. The ease of dehydrohalogenation of alkyl halide with alcoholic KOH is:

1. 3º < 2º < 1º
2. 3º > 2º > 1º
3. 3º < 2º > 1º
4. 3º > 2º < 1º