Namma Kalvi - The No.1 Educational Website for 9th, 10th, 11th, 12th, TRB TET & TNPSC Materials www.nammakalvi.weebly.com Material by Mr. Ravi N, Lecturer in Chemistry, Government Girls' Hr. Sec. School, Kathirkamam, Puducherry - 605 009. www.chem-brains.blogspot.in