Assertion : Change in colour of acidic solution of potassium dichromate by breath is used to test drunk driver.

Reason : Change in colour is due to the complexation of alcohol with potassium di chromate.

• If both assertion and reason are true and reason is the correct explanation of the assertion.

• If both assertion and reason are true but reason is not the correct explanation of the assertion.

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.

312.

Assertion : SiF₆^2- is known but SiCl₆^2- is not.

Reason : Size of fluorine is small and its lone pair of electrons interacts with d-orbitals of Si strongly.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Transition metals are related to which block ?

• 's' block

• 'p' block

• 'd' block

• none of these

The general electronic configuration of transition elements, is :

• (n-1)d^1-5 ns⁰

• (n-1)d^1-10 ns¹

• (n-1)d^1-10 ns²

• (n-1)d^1-10 ns^1-2

Which of the following element does not show variable valency ?

• Ni

• Zn

• Cu

• Mn

For decolourization of 1 mole of KMnO₄, the moles of H₂O₂ required is

• 1/2

• 3/2

• 5/2

• 7/2

Lanthanide for which +II and +III oxidation states are common is

• La

• Nd

• Ce

• Eu

The compound used for gravimetric estimation of copper(II) is

• Cu₂(SCN)₂

• Cu₂O

• Cu₂I₂

• Cu₂CO₃

Which of the following has highest second  ionization energy?

• Ni

• V

• Cr

• Mn

Which of the following compound is not coloured?

• Na₂[CuCl₄]

• Na₂[CdCl₄]

• K₄[Fe(CN)₆]

• K₃[Fe(CN)₆]