A shiny brown-coloured element 'X' on heating in air becomes black in colour. Name the element 'X' and the black-coloured compound formed.

Explain the following facts:transition elements form coloured compounds

The atomic number of an element X is 20 while the atomic number of an element Y is 24.What is the nature of the bond formed between X and Y?Give the electron-dot structure of the compound formed.

A blackish brown coloured solid 'A' when fused with alkali metal hydroxides in presence of air, produces a dark green coloured compound 'B' which on electrolytic oxidation in alkaline medium gives a dark purple coloured compound 'C' Identify A, B and C and write the reactions involved.

Atoms of element X form hcp lattice and those of element Y form occupy 2/3rd of the tetrahedral voids. Determine the formula of the compound formed by the elements X and Y?

choose the correct answer Two elements X (at wt.75) and Y(at w.t.16) combine to gove a compound having 75.8% of X. The formula of the compound is.

An organic compound 'A' having molecular formula C_6H_6O gives a characteristic colour with aqeuous FeCI_3 solution. When 'A' is treated with CO_2 and NaOH at 400K under pressure 'B' is obtained. The compound B on acidification gives compound C which react with acetyl chloride to form D which is a popular pain killer. Deduce the structure of A, B, C and D.