There are some deposits of nitrates and phosphates in earth's crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily. Ammonia forms large number of complexes with transition metal ions. Hybridization easily explains the ease of sigma donation capability of $\mathrm{NH}_{3}$ and $\mathrm{PH}_{3}$. Phosphine is a flammable gas and is prepared from white phosphorous. 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

p-Block Elements — JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 Question with Solution

There are some deposits of nitrates and phosphates in earth's crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily. Ammonia forms large number of complexes with transition metal ions. Hybridization easily explains the ease of sigma donation capability of

NH_{3}

and

PH_{3}

. Phosphine is a flammable gas and is prepared from white phosphorous.

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

(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✓ Correct
(D)Oxidation of nitrates is possible in soil

Answer: (C)

Solution

From the passage, it is stated that "There are some deposits of nitrates and phosphates in earth's crust" and "Nitrates are more soluble in water."

Phosphates are more abundant in the earth's crust than nitrates. Nitrates are more soluble and are easily leached away, making them less abundant as deposits. Phosphates have significant biological importance (DNA, ATP, bones). Nitrates are already in a high oxidation state (+5 for N) and undergo reduction, not oxidation, in soil.

Therefore, statement (C) is correct.

JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · Single correct option

JEE Advanced · 2008 · 13 Apr 2008 · Paper 1 · p-Block Elements

Solution

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