A carboxylic acid (molecular formal C₂H₄O reacts with an alcohol in the presence of an acid catalyst to form a compound 'X'. The alcohol on oxidation with alkaline KMn0₄ followed by acidification gives the same carboxylic acid C₂H₄O₂ Write the name and structure of (i) carboxylic acid, (ii) alcohol and (iii) the compound 'X'.

What are decomposers? List two important roles they play in the environment. 2

What are homologous series of carbon compounds? Write the molecular formula of two consecutive members of homologous series of aldehydes. State which part of the compounds determines their (i) physical and (ii) chemical properties.

The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modem periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.

Study the following table in which positions of six elements A, B, C, D, E arid F are shown as they are in the modem periodic table:

On the basis of the above table, answer the following questions:

(i) Name the element which forms only covalent compounds.

(ii) Name the element which is a metal with valency three.

(iii) Name the element which is a non-metal with valency three.

(iv) Out of D and E, which is bigger in size and why?

(v) Write the common name for the family to which the elements C and F belong.