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The p-Block Elements — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryThe p-Block Elements5 Marks
Question
  1. Which poisonous gas is evolved when white phosphorus is heated with conc. $NaOH$ solution? Write the chemical equation.
  2. Write the formula of first noble gas compound prepared by $N$. Bartlett. What inspired $N$. Bartlett to prepare this compound?
  3. Fluorine is a stronger oxidizing agent than chlorine. Why?
  4. Write one use of chlorine gas.
  5. Complete the following equation: $CaF_2 + H_2SO_4 \xrightarrow{\text{ }\ \ \ \ \ \ \ \ \ \ \ \ }$
✓

Answer

  1. $\text{PH}_{3}\ \ \ \ \ \ \ \ \ \text{P}_{4}+\text{3NaOH}+\text{3H}_{2}\text{O}\xrightarrow{\text{ }\ \ \ \ \ \ \ \ \ \ \ \ }\text{3NaH}_{2}\text{PO}_{2}+\text{PH}_{3}$
  2. $Xe+[PtF_6]^–,$ Approximately same molecular size of $Xe\ \&\ O_2/$Comparable ionisation energies of $Xe\ \&\ O_2$​​​​​​​
  3. It is due to
  1. Low enthalpy of dissociation of $F-F$ bond
  2. High hydration enthalpy of $F^–.$
  1.  
  1. For bleaching wood pulp $($required for manufacture of paper and rayon$),$ cotton and textiles.
  2. In the metallurgy $($extraction$)$ of gold and platinum.
  3. In the manufacture of dyes, drugs and organic compounds such as $CHCl_3, CCl_4, DDT,$ refrigerants $(CCl_2F_2, $ freon$), $ and bleaching powder.
  4. In the preparation of poisonous gases such as phosgene $(COCl_2)$, tear gas $(CCl_3NO_2)$, mustard gas $(ClCH_2CH_2SCH_2CH_2Cl),$ etc. Mustard gas was used by Germany in World War I.
  5. In sterilizing drinking water.
  1. $\text{CaF}_{2}+\text{H}_{2}\text{SO}_{4}\xrightarrow{\text{ }\ \ \ \ \ \ \ \ \ \ \ \ }\text{CaSO}_{4}+\text{2HF}$

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