Scientific Research Publishing

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53970#.VN2sRizQrzE Author(s)   Eman Alzahrani Affiliation(s) Chemistry Department, Faculty of Science, Deanship of Scientific Research, Taif University, Taif, KSA . ABSTRACT Green chemistry methods for production of nanoparticles have many advantages, such as ease of use, which makes the methods desirable and economically viable. The aim of the present work was to green synthesise silver nanoparticles (SNPs) using aqueous tangerine peel extract in different ratios (2:1, 1:1, 1:2). The formed SNPs were characterised using ultraviolet-visible (UV-Vis) spectrophotometry, and transmission electron microscopy (TEM). The UV-Vis spectra showed that the highest absorbance was observed when the ratio of peel tangerine extract to silver nitrate solution was 1:2. The transmission electron micrographs showed the formation of poly dispersed nanoparticles. It was f...

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53445#.VMWw7izQrzE Author(s)    Dixa Singh , Vimal Sheel Singh Affiliation(s) Department of Chemistry, H. N. B. Garhwal University Campus-Pauri (Uttarakhand), Pauri, India . ABSTRACT The aqueous and alcoholic extract of Urena lobata flowers has been used in acid/alkali titrations over a wide range of concentration. The results obtained with the flower extracts have been compared with those obtained by using traditional chemical indicators like phenolphthalein and methyl orange. It has been established experimentally that the flower extract can be successfully used in place of phenolphthalein and methyl orange for acid/alkali titrations. The presence of anthocyanins is supposed to impart pH sensitive colour dependence to the natural indicator.   KEYWORDS Urena lobata Flowers , Phenolphthalein , Methyl Orange , Acid-Base Titration , Anth...