A covalent bond is formed when two atoms reach a stable state that balances: MARK TWO RESPONSES

A
the repulsion between the nucleus protons of one atom to the electrons of the other atom

B
the attraction between the nucleus of one atom to the electrons of the other atom

C
the attraction between the two nuclei of the atoms, which both contain protons

D
the repulsion between the two nuclei of the atoms, which both contain protons

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2