- AUracil and adenine; cytosine and guanine
- ✓Adenine and thymine; guanine and cytosine
- CAdenine and thymine; guanine and uracil
- DAdenine and guanine; thymine and cytosine
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$(A)$ $H _2 S _2 O _7$ $(B)$ $H _2 S _2 O _8$ $(C)$ $H _2 S _2 O _5$ $(D)$ $H _2 SO _5$
(Rounded-off to the nearest integer)
$1.$ Among the following, the correct statement is
$(A)$ Phosphates have no biological significance in humans
$(B)$ Between nitrates and phosphates, phosphates are less abundant in earth's crust
$(C)$ Between nitrates and phosphates, nitrates are less abundant in earth's crust
$(D)$ Oxidation of nitrates is possible in soil
$2.$ Among the following, the correct statement is
$(A)$ Between $\mathrm{NH}_3$ and $\mathrm{PH}_3, \mathrm{NH}_3$ is better electron donor because the lone pair of electrons occupies spherical ' $\mathrm{s}$ ' orbital and is less directional
$(B)$ Between $\mathrm{NH}_5$ and $\mathrm{PH}_5, \mathrm{PH}_5$ is better electron donor because the lone pair of electrons occupies $\mathrm{sp}^3$ orbital and is more directional
$(C)$ Between $\mathrm{NH}_3$ and $\mathrm{PH}_3, \mathrm{NH}_3$ is a better electron donor because the lone pair of electrons occupies $\mathrm{sp}^3$ orbital and is more directional
$(D)$ Between $\mathrm{NH}_3$ and $\mathrm{PH}_3, \mathrm{PH}_3$ is better electron donor because the lone pair of electrons occupies spherical ' $\mathrm{s}$ ' orbital and is less directional
$3.$ White phosphorus on reaction with $\mathrm{NaOH}$ gives $\mathrm{PH}_3$ as one of the products. This is a
$(A)$ dimerization reaction
$(B)$ disproportionation reaction
$(C)$ condensation reaction
$(D)$ precipitation reaction
Give the answer question $1,2$ and $3.$