671.

Essential component of amalgam is :

• Fe

• Pb

• Hg

• Cr

The compound used in enrichment ofuranium for nuclear power plant is

• U₃O₈

• UF₆

• UO₂(NO₃)₂

• UCl₄

What is the name of element with atomic number 105 ?

• Kurchatovium

• Dubnium

• Nobelium

• Holmium

What is the general outer electronic configuration of the coinage metals ?

• ns² np⁶

• (n-1)d¹⁰ ns¹

• (n-1)d¹⁰ ns²

• (n-1)d⁹ ns²

Assertion : ${\mathrm{E}}^{°}$ for Mn³⁺/Mn²⁺ is more positive than Cr³⁺/Cr³⁺

Reason : The third ionization energy of Mn is larger than that of Cr.

• 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.

Assertion : K₂Cr₂O₇ is used as primary standard in volumetric analysis.

Reason : It has a good solubility in water.

• 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.

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.

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