Question:
Given below are two statements:
Statement-I: The oxidation state of phosphorus in the sodium salt of oxoacid formed when white phosphorus reacts with aqueous alkali solution is +1.
Statement-II: Sulphur gives two gaseous products when treated with conc. \(HNO_3\).
Given below are two statements:
Statement-I: The oxidation state of phosphorus in the sodium salt of oxoacid formed when white phosphorus reacts with aqueous alkali solution is +1.
Statement-II: Sulphur gives two gaseous products when treated with conc. \(HNO_3\).
Show Hint
Remember the reaction:
\[
P_4 + 3NaOH + 3H_2O
\rightarrow
PH_3 + 3NaH_2PO_2
\]
The oxidation state of phosphorus in hypophosphite ion \((H_2PO_2^-)\) is \(+1\). This is a frequently asked examination fact.
Updated On: Jun 17, 2026
- Both statements I and II are correct
- Statement I is correct but statement II is not correct
- Statement I is not correct but statement II is correct
- Both statements I and II are not correct
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Concept:
White phosphorus reacts with hot aqueous alkali to form phosphine and sodium hypophosphite.
\[
P_4 + 3NaOH + 3H_2O
\rightarrow
PH_3 + 3NaH_2PO_2
\]
The oxidation state of phosphorus can be calculated using oxidation number rules.
Further, sulphur reacts with concentrated nitric acid as an oxidizing agent and gets converted into sulphuric acid.
Step 1: Identify the oxoacid salt formed in the reaction of white phosphorus with alkali.
White phosphorus reacts with aqueous sodium hydroxide according to the reaction \[ P_4 + 3NaOH + 3H_2O \rightarrow PH_3 + 3NaH_2PO_2 \] The sodium salt formed is sodium hypophosphite \[ NaH_2PO_2 \] which is derived from hypophosphorous acid \[ H_3PO_2. \]
Step 2: Calculate the oxidation state of phosphorus in \(H_2PO_2^{-}\).
Let the oxidation state of phosphorus be \(x\). For the ion \(H_2PO_2^{-}\), \[ x+2(+1)+2(-2)=-1 \] \[ x+2-4=-1 \] \[ x-2=-1 \] \[ x=+1 \] Hence, the oxidation state of phosphorus is \[ \boxed{+1} \] Therefore Statement-I is correct.
Step 3: Examine Statement-II.
Sulphur reacts with concentrated nitric acid and gets oxidized to sulphuric acid. \[ S + 6HNO_3 \rightarrow H_2SO_4 + 6NO_2 + 2H_2O \] Only one gaseous product, \[ NO_2 \] is produced. Hence the statement that sulphur gives two gaseous products is incorrect. Therefore Statement-II is false.
Step 4: Draw the final conclusion.
\[ \text{Statement-I is True} \] \[ \text{Statement-II is False} \] Hence, \[ \boxed{\text{Statement I is correct but Statement II is not correct}} \]
Step 1: Identify the oxoacid salt formed in the reaction of white phosphorus with alkali.
White phosphorus reacts with aqueous sodium hydroxide according to the reaction \[ P_4 + 3NaOH + 3H_2O \rightarrow PH_3 + 3NaH_2PO_2 \] The sodium salt formed is sodium hypophosphite \[ NaH_2PO_2 \] which is derived from hypophosphorous acid \[ H_3PO_2. \]
Step 2: Calculate the oxidation state of phosphorus in \(H_2PO_2^{-}\).
Let the oxidation state of phosphorus be \(x\). For the ion \(H_2PO_2^{-}\), \[ x+2(+1)+2(-2)=-1 \] \[ x+2-4=-1 \] \[ x-2=-1 \] \[ x=+1 \] Hence, the oxidation state of phosphorus is \[ \boxed{+1} \] Therefore Statement-I is correct.
Step 3: Examine Statement-II.
Sulphur reacts with concentrated nitric acid and gets oxidized to sulphuric acid. \[ S + 6HNO_3 \rightarrow H_2SO_4 + 6NO_2 + 2H_2O \] Only one gaseous product, \[ NO_2 \] is produced. Hence the statement that sulphur gives two gaseous products is incorrect. Therefore Statement-II is false.
Step 4: Draw the final conclusion.
\[ \text{Statement-I is True} \] \[ \text{Statement-II is False} \] Hence, \[ \boxed{\text{Statement I is correct but Statement II is not correct}} \]
Was this answer helpful?
0
0
Top TS EAMCET Chemistry Questions
- A, B and C are three biomolecules. The results of the tests performed on them are given below :A, B and C are respectively :
Molisch's lest Barfoed Test Biuret Test A Positive Negative Negativde B Positive Positive Negative C Negative Negative Positive - 1 mole of $H_2$ and 2 moles of $I_2$ are taken initially in a 2 litre vessel. The number of moles of $H_2$ at equilibrium is 0.2. Then the number of moles of $I_2$ and HI at equilibrium is
- The pH of a buffer containing equal molarconcentration of a weak base and its chloride ( $K_b$ for weak base = $2 \times 10^{-5}$, log 2 = 0.3) is
- Atomic radius (pm) of Al, Si, N and F respectively is
- Consider the following electrode process of a cell, $ {Cl^{-1} -> \frac{1}{2} Cl_2 + e^{-}}$ $ {[MCl + e^{-} -> M + Cl^{-} ] }$ If EMF of this cell is $-1.140\, V$ and $E^0$ value of the cell is $-0.55\,V$ at $298\,K$, the value of the equilibrium constant of the sparingly soluble salt MCl is in the order of
View More Questions
Top TS EAMCET d -and f -Block Elements Questions
Among the following the incorrect statement about transition metals is
- Which of the following is correct statement?
- Which of the following does not exist?
- \(E^\circ_{M^{2+}/M}\) (in V) is highest for
- The number of moles of oxalate ions oxidized by one mole of permanganate ions in acidic medium is
View More Questions
Top TS EAMCET Questions
- A bag contains $5$ red balls, $3$ black balls and $4$ white balls are drawn at random. The probability that they are not of same colour is
- If $cosec\, \theta - \cot \theta = 2017$, then quadrant in which $\theta $ lies is
- If $a$ is a unit vector, then $| a \times \hat{ i }|^{2}+| a \times \hat{ j }|^{2}+| a \times \hat{ k }|^{2}=$
- $A$ straight line makes an intercept on the $Y$-axis twice as long as that on $X$-axis and is at a unit distance from the origin. Then the line is represented by the equations
- Let $S$ and $S'$ be the foci of an ellipse and B be one end of its minor axis. If $SBS'$ is an isosceles right angled triangle then the eccentricity of the ellipse is
View More Questions