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CBSE

Chemistry

NEET Chemistry : Classification of Elements and Periodicity in Properties

71.

The pair of amphoteric hydroxides is

72.

Assertion: The correct order of oxidising power is :

${VO}_{2}^{+}$ < ${Cr}_{2} O_{7}^{2 -} < M n O_{4}^{-}$

Reason: The oxidation state of Mn is +7

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.

73.

Which of the following element has lowest melting point?

74.

Assertion : Helium is used in diving apparatus.

Reason : Solubility of helium is less in blood.

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.

75.

Which of the following is correct?

76.

Assertion : The position of an element in periodic table after emission of one $α -$ and two $β$ - particles remains unchanged.

Reason : Emission of one $α -$ and two $β -$ particles give isotope of the element which acquires same position in periodic table

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.