Question

Element X is the lightest element of group 7 of periodic table which forms oxo-anion in +6 oxidation state. The colour of potassium salt of the oxo-anion is:

• A. Green
• B. Orange
• C. Yellow
• D. Brown

Hint:

Do not confuse manganate (green) with permanganate (purple).

Answer 1

The Correct Option is A

Step 1: Identify the element.
Group 7 elements are Mn, Tc, Re.
Lightest among them is manganese (Mn).
Step 2: Identify the oxo-anion in +6 oxidation state.
Manganese in +6 oxidation state forms manganate ion:
\[ MnO_4^{2-} \]
Step 3: Colour of potassium manganate.
Potassium manganate (K$_2$MnO$_4$) is green in colour.