Asubstance has a freezing point of 24 °c. which of the following is true for the substance?
when the substance is heated, its temperature will start rising above 24 °c after 50% of the liquid has changed to vapors.
when the substance is heated, its temperature will start rising above 24 °c after 100% of the solid has changed to liquid.
when the substance is cooled, its temperature will fall below 24 °c after 100% of the vapors have changed to liquid.
when the substance is cooled, its temperature will fall below 24 °c after 50% of the liquid has changed to solid.

l dont know l am s sorry

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

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.