In the equation, 2al (s) + 3cl2 (g) → 2alcl3 (s), the large number “3” in front of the cl2 indicates:

the number of chlorine atoms needed to balance the equation

the number of chloride molecules needed to balance the equation

the number of moles of chlorine atoms needed to balance the equation

the number of moles of chlorine molecules needed to balance the equation

In the equation,

2Al(s) + 3Cl2(g) —> 2AlCl3(s),

the large number "3" in front of Cl2 indicates the the number of moles of Chlorine molecules needed to balance the equation.

Hope this will help you. 

If you like my answer. Please mark it as brainliest  And  Be my follower if possible.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.