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4. d and f- block elements — Chemistry STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceChemistry4. d and f- block elements1 Mark
MCQ
Which of the following statements is false ?
  • ✓
    $Na_2Cr_2O_7$ is less soluble than $K_2Cr_2O_7$
  • B
    $Na_2Cr_2O_7$ is primary standard in volumetry
  • C
    $CrO_4^{2-}$ is tetrahedral in shape
  • D
    $CrO_7^{2-}$ has a $Cr- O- Cr$ bond
✓

Answer

Correct option: A.
$Na_2Cr_2O_7$ is less soluble than $K_2Cr_2O_7$
a
$Na_2Cr_2O_7$ is used as primary standard in volumetry

Hydration energy of $Na^+$ is greater then $K^+$. Because of smaller size of $Na^+$ , $Na_2Cr_2O_7$ is more soluble than $K_2Cr_2O_7$. 

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