Write the structural formula of following : 2-(4-isobutyphenyl)propanoic acid.

Explanation

Ordinary filter paper is permeable to colloidal dispersions (pores being of colloidal size) as well as to true solution and thus cannot be employed for filtration. A filter paper treated with colloidon or gelatin solution followed by hardening by dipping in form of aldehyde solution serves the purpose (`because` due to the treatment pore size of filter paper is reduced).