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Question

Consider the following reactions :
$\text{NaCl} + \text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 \rightarrow \text{A} + \text{KHSO}_4 + \text{NaHSO}_4 + \text{H}_2\text{O}$
$\text{A} + \text{NaOH} \rightarrow \text{B} + \text{NaCl} + \text{H}_2\text{O}$
$\text{B} + \text{H}_2\text{SO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{C} + \text{Na}_2\text{SO}_4 + \text{H}_2\text{O}$
In the product 'C', 'X' is the number of $\text{O}_2^{2-}$ units, 'Y' is the total number oxygen atoms present and 'Z' is the oxidation state of Cr. The value of X + Y + Z is ____________.

Chemical Reaction Analysis and Calculation

Chromyl Chloride Formation: Product A

The first reaction describes the synthesis of chromyl chloride ($\text{CrO}_2\text{Cl}_2$), which is known for its characteristic red vapours, from sodium chloride ($\text{NaCl}$), potassium dichromate ($\text{K}_2\text{Cr}_2\text{O}_7$), and sulfuric acid ($\text{H}_2\text{SO}_4$).

The balanced reaction is:

$ 4\text{NaCl} + \text{K}_2\text{Cr}_2\text{O}_7 + 6\text{H}_2\text{SO}_4 \rightarrow 2\text{CrO}_2\text{Cl}_2 \uparrow + 2\text{KHSO}_4 + 4\text{NaHSO}_4 + 3\text{H}_2\text{O} $

Therefore, product 'A' is $\text{CrO}_2\text{Cl}_2$.

Sodium Chromate Identification: Product B

Product 'A', chromyl chloride ($\text{CrO}_2\text{Cl}_2$), reacts with sodium hydroxide ($\text{NaOH}$). This reaction yields sodium chromate ($\text{Na}_2\text{CrO}_4$) along with sodium chloride ($\text{NaCl}$) and water ($\text{H}_2\text{O}$).

The balanced reaction is:

$ \text{CrO}_2\text{Cl}_2 + 4\text{NaOH} \rightarrow \text{Na}_2\text{CrO}_4 + 2\text{NaCl} + 2\text{H}_2\text{O} $

Thus, product 'B' is $\text{Na}_2\text{CrO}_4$ (sodium chromate).

Perchromate Identification: Product C Parameters

In the third reaction, sodium chromate ($\text{B}$) reacts with sulfuric acid ($\text{H}_2\text{SO}_4$) and hydrogen peroxide ($\text{H}_2\text{O}_2$) to form product 'C'. This is a standard method for forming perchromate species.

The relevant reaction forming the perchromate ion ($\text{CrO}_5^{2-}$) is:

$ \text{CrO}_4^{2-} + \text{H}_2\text{SO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{CrO}_5^{2-} + \text{SO}_4^{2-} + 2\text{H}_2\text{O} $

Product 'C' is the perchromate ion ($\text{CrO}_5^{2-}$).

We need to determine X, Y, and Z for 'C':

  • X: Number of $\text{O}_2^{2-}$ units: The structure of the perchromate ion ($\text{CrO}_5^{2-}$) contains two peroxy linkages ($O-O$). This means it contains two $\text{O}_2^{2-}$ units. So, X = 2.
  • Y: Total number of oxygen atoms: The formula $\text{CrO}_5^{2-}$ indicates a total of 5 oxygen atoms. So, Y = 5.
  • Z: Oxidation state of Cr: In perchromate, chromium is in the +6 oxidation state. So, Z = 6.

Final Calculation: X + Y + Z Value

The question asks for the value of X + Y + Z. Using the values determined above:

$ X + Y + Z = 2 + 5 + 6 $

$ X + Y + Z = 13 $

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Similar Questions

  1. A chromium complex with a formula $\text{CrCl}_3\cdot 6\text{H}_2\text{O}$ has a spin only magnetic moment value of $3.87 \text{ BM}$ and its solution conductivity corresponds to $1 : 2$ electrolyte. $2.75 \text{ g}$ of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of $\text{AgNO}_3$. The amount of $\text{AgCl}$ formed in the above process is _____ g. (Nearest integer)
    [Given: Molar mass in $\text{g mol}^{-1}$ $\text{Cr} : 52; \text{Cl}: 35.5, \text{Ag}: 108, \text{O}: 16, \text{H}: 1$]
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  3. The crystal field splitting energy of $[\text{Co(oxalate)}_3]^{3-}$ complex is '$n$' times that of the $[\text{Cr(oxalate)}_3]^{3-}$ complex. Here '$n$' is ___________. (Assume $\Delta_o >> P$)

  4. A metal complex with a formula $MCl_4.3NH_3$ is involved in $sp^3d^2$ hybridisation. It upon reaction with excess of $AgNO_3$ solution gives 'x' moles of AgCl. Consider 'x' is equal to the number of lone pairs of electron present in central atom of $BrF_5$. Then the number of geometrical isomers exhibited by the complex is ______
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Important Questions from Inorganic Chemistry

  1. A chromium complex with a formula $\text{CrCl}_3\cdot 6\text{H}_2\text{O}$ has a spin only magnetic moment value of $3.87 \text{ BM}$ and its solution conductivity corresponds to $1 : 2$ electrolyte. $2.75 \text{ g}$ of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of $\text{AgNO}_3$. The amount of $\text{AgCl}$ formed in the above process is _____ g. (Nearest integer)
    [Given: Molar mass in $\text{g mol}^{-1}$ $\text{Cr} : 52; \text{Cl}: 35.5, \text{Ag}: 108, \text{O}: 16, \text{H}: 1$]
  2. Identify the metal ions among $\text{Co}^{2+}, \text{Ni}^{2+}, \text{Fe}^{2+}, \text{V}^{3+}$ and $\text{Ti}^{2+}$ having a spin-only magnetic moment value more than $3.0\text{ BM}$. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is __________.
  3. The crystal field splitting energy of $[\text{Co(oxalate)}_3]^{3-}$ complex is '$n$' times that of the $[\text{Cr(oxalate)}_3]^{3-}$ complex. Here '$n$' is ___________. (Assume $\Delta_o >> P$)

  4. Which of the following is the structure of pyrosulphuric acid?
  5. The correct order of conductivity of $0.001\text{ (M)}$ separate aqueous solutions of $[Pt(NH_3)_6]Cl_4\text{ (i)}$; $[Cr(NH_3)_6]Cl_3\text{ (ii)}$; $[Co(NH_3)_4Cl_2]Cl\text{ (iii)}$ and $K_2PtCl_6\text{ (iv)}$ each containing octahedral complex species is
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