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    JEE Main Exam Pattern 2026 (Released) - New Paper Pattern, Total Marks, No. of Questions

    Phosphine and Phosphorus Chloride - Practice Questions & MCQ

    Edited By admin | Updated on Sep 18, 2023 18:35 AM | #JEE Main

    Quick Facts

    • Phosphine and Phosphorus Chloride is considered one of the most asked concept.

    • 42 Questions around this concept.

    Solve by difficulty

    Identify the incorrect statement for $
    \mathrm{PCl}_5
    $ from the following.

    The formal change in the phosphorus in the compound is obtained by the absorption of phosphine in HI.

    The hydrolysis product of calcium phosphide is :

    Which gas is used in Holme's signals 

    Which of the following gas is poisonous with rotten fish smell

    The solid $\mathrm{PCl}_5$  exists as

    The basicity of the acid produced on the hydrolysis of $P_4 O_{10}$ is:

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    The formula of phosphinic acid is : 

    Which compound of phosphorus is prepared by the following reaction:

    $\mathrm{P}_4+\mathrm{SO}_2 \mathrm{Cl}_2 \rightarrow$

     

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    Which of the following compound is a colourless oily liquid

    Concepts Covered - 0

    Phosphine and Phosphorus Chloride

    PHOSPHINE

    • Preparation
      Phosphine is prepared by the reaction of calcium phosphide with water or dilute HCl.
      \mathrm{Ca_{3}P_{2}\: +\: 6H_{2}O\: \rightarrow \: 3Ca(OH)_{2}\: +\: 2PH_{3}}
      \mathrm{Ca_{3}P_{2}\: +\: 6HCl\: \rightarrow \: 3CaCl_{2}\: +\: 2PH_{3}}
      In the laboratory, it is prepared by heating white phosphorus with concentrated NaOH solution in an inert atmosphere of CO2.
      \mathrm{P_{4}\: +\: 3NaOH\: +\: 3H_{2}O\: \rightarrow \: PH_{3}\: +\: 3NaH_{2}PO_{2}}
      When pure, it is non-inflammable but becomes inflammable owing to the presence of P2H4 or P4 vapours. To purify it from the impurities, it is absorbed in HI to form phosphonium iodide (PH4I) which on treating with KOH gives off phosphine.
      \mathrm{PH_{4}I\: +\: KOH\: \rightarrow \: KI\: +\: H_{2}O\: +\: PH_{3}}
       
    • Properties
      It is a colourless gas with the rotten fish smell and is highly poisonous. It explodes on contact with traces of oxidising agents like HNO3, Cl2 and Br2 vapours. It is slightly soluble in water. The solution of PH3 in water decomposes in presence of light giving red phosphorus and H2. When absorbed in copper sulphate or mercuric chloride solution, the corresponding phosphides are obtained.
      \mathrm{3CuSO_{4}\: +\: 2PH_{3}\: \rightarrow \: Cu_{3}P_{2}\: +\: 3H_{2}SO_{4}}
      \mathrm{3HgCl_{2}\: +\: 2PH_{3}\: \rightarrow \: Hg_{3}P_{2}\: +\: 6HCl}
    • Uses
      The spontaneous combustion of phosphine is technically used in Holme’s signals. Containers containing calcium carbide and calcium phosphide are pierced and thrown in the sea when the gases evolved burn and serve as a signal. It is also used in smoke screens.

    PHOSPHORUS  TRICHLORIDE

    • Preparation

    It is obtained by passing dry chlorine over heated white phosphorus.
    \mathrm{P_4 + 6Cl_2 \longrightarrow 4\ PCl_3}
    It can also obtained by the action of thionyl chloride with white phosphorus.
    \mathrm{P_4 + 8\ SOCl_2 \longrightarrow 4\ PCl_3 + 4\ SO_2+ 2\ S_2Cl_2}

    • Properties

    It is a colourless oily liquid and hydrolyses in the presence of moisture.
    \mathrm{PCl_3 + 3\ H_2O \longrightarrow H_3PO_3+ 3\ HCl}

    It reacts with organic compounds containing –OH group and replaces it with a -Cl group 
    \mathrm{RCOOH + PCl_3 \longrightarrow RCOCl+ H_3PO_3}

    \mathrm{RCH_2OH + PCl_3 \longrightarrow RCH_2Cl+ H_3PO_3}

    PHOSPHORUS  PENTACHLORIDE

    • Preparation

    It is obtained by reaction of excess dry chlorine with white phosphorus.
    \mathrm{P_4 + 10\ Cl_2 \longrightarrow 4\ PCl_5}
    It can also obtained by the reaction of sulphuryl chloride with white phosphorus.
    \mathrm{P_4 + 10\ SO_2Cl_2 \longrightarrow 4\ PCl_5 + 10\ SO_2}

    • Properties

    It is a colourless oily liquid and hydrolyses in the presence of moisture.
    \mathrm{PCl_5 + H_2O \longrightarrow POCl_3+ 2\ HCl} 
    (partial hydrolysis)

    \mathrm{POCl_3 + 3\ H_2O \longrightarrow H_3PO_4+ 3\ HCl} (complete hydrolysis)

    It reacts with organic compounds containing –OH group and replaces it with a -Cl group 

    \mathrm{RCOOH + PCl_5 \longrightarrow RCOCl+ POCl_3 + HCl}

    \mathrm{RCH_2OH + PCl_5 \longrightarrow RCH_2Cl+ POCl_3 +HCl}

    It can convert finely divided metals into their corresponding chlorides on heating 

    \mathrm{2Ag + PCl_5 \longrightarrow 2AgCl+ PCl_3}

    \mathrm{Sn +2\ PCl_5 \longrightarrow SnCl_4+ 2\ PCl_3}

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