Which element’s symbol could replace the question mark in the diagram? boron (B)
neon (Ne)
rubidium (Rb)
arsenic (As)

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong