The second day Prayers for Navratri is dedicated to Goddess Brahmacharini. Navratri Day 2 Mantra in Hindi is given below. It is chanted on October 14, 2015 and October 15 during Navratri. There are three mantras. First is Mool Mantra for second day of Navratri. Second is Dhyan Shloka dedicated to Goddess Brahmacharini. Third is a Stotra. You can chant also prayers like Lalita Sahasranama on the day.
There is no need to chant all mantras. Most devotees chant just the mool mantra.