JEE Main 2022 (Online) 29th July Evening Shift | d and f Block Elements Question 66 | Chemistry

Which of the following $$3\mathrm{d}$$-metal ion will give the lowest enthalpy of hydration $$\left(\Delta_{\text {hyd }} \mathrm{H}\right)$$ when dissolved in water ?

$$\mathrm{Cr}^{2+}$$

$$\operatorname{Mn}^{2+}$$

$$\mathrm{Fe}^{2+}$$

$$\mathrm{Co}^{2+}$$

JEE Main 2022 (Online) 29th July Morning Shift

MCQ (Single Correct Answer)

-1

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives :

$$\mathrm{Zn}(\mathrm{OH})_{2}$$

$$\mathrm{ZnO}$$

$$\left[\mathrm{Zn}(\mathrm{OH})_{4}\right]^{2-}$$

$$\left[\mathrm{ZnO}_{2}\right]^{2-}$$

JEE Main 2022 (Online) 29th July Morning Shift

MCQ (Single Correct Answer)

-1

In following pairs, the one in which both transition metal ions are colourless is :

$$\mathrm{Sc}^{3+}, \mathrm{Zn}^{2+}$$

$$\mathrm{Ti}^{4+}, \mathrm{Cu}^{2+}$$

$$\mathrm{V}^{2+}, \mathrm{Ti}^{3+}$$

$$\mathrm{Zn}^{2+}, \mathrm{Mn}^{2+}$$

JEE Main 2022 (Online) 29th July Morning Shift

MCQ (Single Correct Answer)

-1

In neutral or faintly alkaline medium, $$\mathrm{KMnO}_{4}$$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :