MCQ
Guanine is an example of:
- AA nitrogenous base
- BA nucleoside
- CA nucleotide
- DPhosphate
Explanation:
The four nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C) and thymine (T).
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$\begin{array}{*{20}{c}}
{Ph - C{H_2} - CH - C{H_3}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,OH\,}
\end{array}$ $>$ $\begin{array}{*{20}{c}}
{Me - C{H_2} - CH - C{H_3}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,OH\,}
\end{array}$
Assertion $A$ : $\left[ CoCl \left( NH _3\right)_5\right]^{2+}$ absorbs at lower wavelength of light with respect to $\left[ Co \left( NH _3\right)_5\left( H _2 O \right)\right]^{3+}$
Reason $R$ : It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.
In the light of the above statements, choose the correct answer from the options given below :
$\left( C _6 H _5\right)_3 C - Cl \frac{ OH ^{-}}{\text {Pyridine }}\left( C _6 H _5\right)_3 C - OH$
| Observation | $[A]$ | $[B]$ | Rate of reaction |
| $1$ | $0.1$ | $0.1$ | $2 \times {10^{ - 3}}\,mol\,{L^{ - 1}}{\sec ^{ - 1}}$ |
| $2$ | $0.4$ | $0.1$ | $0.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}{\sec ^{ - 1}}$ |
| $3$ | $0.1$ | $0.2$ | $1.4 \times {10^{ - 2}}\,mol\,{L^{ - 1}}{\sec ^{ - 1}}$ |