Question

L, M and N are three elements with atomic numbers 13, 7 and 10 respectively. Answer the following question using only the alphabets given. Do not identify the elements.

Which element can combine with hydrogen to form a gas which produces dense white fumes with concentrated HCl?

Answer 1

Element M (atomic number 7) is the one that combines with hydrogen to form a gas (ammonia), which produces dense white fumes with concentrated HCl.