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 2, 2016 and October 3 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.