Answer
64.8k+ views
Hint:The ortho phosphoric acid has 3 hydroxy groups and one oxo group whereas \[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]has 4 oxo groups.
Complete step by step answer:
Ortho phosphoric acid has the formula \[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\]containing 3 hydroxy groups and one oxo group.
The phosphorus pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]can be converted into ortho phosphoric acid by using 3 molecules of water.
${P_2}{O_5} + 3{H_2}O \to 2{H_3}P{O_4}$
This can be shown in detail by following steps showing how each molecule of water gets used to convert phosphorus pentoxide to ortho phosphoric acid. Phosphorous pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\], reacts with one molecule of water and gets converted to meta Phosphoric acid (\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{3}}}\]).
\[{P_2}{O_5} + {H_2}O \to 2HP{O_3}\]
The meta Phosphoric acid (\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{3}}}\]) formed reacts with another molecule of water and pyro phosphoric acid(\[{{\text{H}}_{\text{4}}}{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{7}}}\]).
\[2HP{O_3} + {H_2}O \to {H_4}{P_2}{O_7}\]
The pyro phosphoric acid(\[{{\text{H}}_{\text{4}}}{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{7}}}\]) formed reacts with another molecule of water and we finally get the ortho phosphoric acid,\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\].
\[{H_4}{P_2}{O_7} + {H_2}O \to {H_3}P{O_3}\]
Therefore, the number of water molecules needed to convert one molecule of\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]into orthophosphoric acid is 3.
So, the correct option is B.
Additional Information: Phosphorous pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]is a good dehydrating agent that can remove water molecule under suitable conditions. Ortho phosphoric acid,\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\] is a mineral acid that can remove rust and also used in processed foods.
Note:
The number of water molecules in a compound depends on the hydroxyl group present in the desired molecule. The hydroxyl group will easily abstract protons from water and molecules can be converted with ease.
Complete step by step answer:
Ortho phosphoric acid has the formula \[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\]containing 3 hydroxy groups and one oxo group.
The phosphorus pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]can be converted into ortho phosphoric acid by using 3 molecules of water.
${P_2}{O_5} + 3{H_2}O \to 2{H_3}P{O_4}$
This can be shown in detail by following steps showing how each molecule of water gets used to convert phosphorus pentoxide to ortho phosphoric acid. Phosphorous pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\], reacts with one molecule of water and gets converted to meta Phosphoric acid (\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{3}}}\]).
\[{P_2}{O_5} + {H_2}O \to 2HP{O_3}\]
The meta Phosphoric acid (\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{3}}}\]) formed reacts with another molecule of water and pyro phosphoric acid(\[{{\text{H}}_{\text{4}}}{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{7}}}\]).
\[2HP{O_3} + {H_2}O \to {H_4}{P_2}{O_7}\]
The pyro phosphoric acid(\[{{\text{H}}_{\text{4}}}{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{7}}}\]) formed reacts with another molecule of water and we finally get the ortho phosphoric acid,\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\].
\[{H_4}{P_2}{O_7} + {H_2}O \to {H_3}P{O_3}\]
Therefore, the number of water molecules needed to convert one molecule of\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]into orthophosphoric acid is 3.
So, the correct option is B.
Additional Information: Phosphorous pentoxide,\[{{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}\]is a good dehydrating agent that can remove water molecule under suitable conditions. Ortho phosphoric acid,\[{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\] is a mineral acid that can remove rust and also used in processed foods.
Note:
The number of water molecules in a compound depends on the hydroxyl group present in the desired molecule. The hydroxyl group will easily abstract protons from water and molecules can be converted with ease.
Recently Updated Pages
Write a composition in approximately 450 500 words class 10 english JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Arrange the sentences P Q R between S1 and S5 such class 10 english JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
What is the common property of the oxides CONO and class 10 chemistry JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
What happens when dilute hydrochloric acid is added class 10 chemistry JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
If four points A63B 35C4 2 and Dx3x are given in such class 10 maths JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
The area of square inscribed in a circle of diameter class 10 maths JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Other Pages
A boat takes 2 hours to go 8 km and come back to a class 11 physics JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
In the ground state an element has 13 electrons in class 11 chemistry JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Differentiate between homogeneous and heterogeneous class 12 chemistry JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Electric field due to uniformly charged sphere class 12 physics JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
According to classical free electron theory A There class 11 physics JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Excluding stoppages the speed of a bus is 54 kmph and class 11 maths JEE_Main
![arrow-right](/cdn/images/seo-templates/arrow-right.png)