B. Maharashtra, Madhya Pradesh, Gujarat and Rajasthan
45.
Which German chemist and physicist proposed that an aromatic compound must have an odd number of pairs of electrons. Which can mathematically be written as 4n+2 (n = 0,1,2,3, etc.) in 1931?
______ became the first swimmer from India to breach the Olympic Qualification Time (A cut) in swimming as he capped the qualification period with an outstanding performance in the Sette Colli Trophy in Rome, Italy in June 2021.