Despite being an extremely rare gas on Earth, hydrogen is the most common element in the universe. This is due to the fact that hydrogen is the fuel for stars, as it undergoes the fusion nuclear reaction to form helium and release the energy to sustain the star. Therefore, the answer to this question is hydrogen.
C will cause too many problems
The correction is D. This is because, the higher the value of K, the greater the relative amount of product present at equilibrium.
(3) The concen<span>tration of the solution remains constant.</span>
The group/family number is the same number of valance electrons.