Ammonia is produced by the following reaction,
3h2(g) + n2(g) - 2nh3(g)
when 7.00 g of hydrogen react with 70.0 g of nitrogen, hydrogen is considered the limiting reactant because
7.5 mol of hydrogen would be needed to consume the available nitrogen.
7.5 mol of nitrogen would be needed to consume the available hydrogen.
hydrogen would produce 7.5 mol more ammonia than nitrogen.
nitrogen yiguld produce 7.5 mol more ammonia than hydrogen.

7.5 moles of hydrogen would be needed to consume available nitrogen.

Explanation:

First of all we will write the balance chemical equation.

3H₂ + N₂ → 2NH₃

Number of moles of hydrogen:

number of moles = mass / molar mass

number of moles = 7 g/ 2 g/mol

number of moles = 3.5 mol

Number of moles of nitrogen:

number of moles = mass / molar mass

number of moles = 70 g/ 28 g/mol

number of moles = 2.5 mol

Now we compare the moles of hydrogen and nitrogen with ammonia from balance chemical equation.

                                            N₂         :        NH₃

                                             1           :          2

                                             2.5       :          2×2.5 = 5 mol

                                             H₂          :          NH₃

                                              3           :             2

                                             3.5         ;             2/3×3.5 =2.3 mol

So the number of moles of ammonia produced from hydrogen are less, hydrogen will be limitting reactant.

The amount of ammonia left:

                                             H₂               :              N₂

                                               3               :              1

                                              3.5             :             1/3×3.5 = 1.2 mol

So the 1.2 moles of nitrogen are react completely with 3.5 moles of hydrogen.

moles of ammonia left = 2.5 - 1.2 = 1.3 moles

If 7.5 moles of hydrogen present:

                                  H₂               :              N₂

                                     3               :              1

                                    7.5             :             1/3×7.5 = 2.5 mol

It means  7.5 mole of hydrogen will consume 2.5 moles of ammonia.