Which of the following signs of a chemical reaction are observed in the reaction of potassium with water? precipitate formed temperature change smell produced gas produced color change

Temperature change and gas produced  

Explanation:

Potassium reacts with water very fast.

The reaction is:

This is an exothermic reaction. There is release of energy or heat in the reaction. Hence a temperature change.

Also there is formation of hydrogen gas.

The solution is colorless.

There is not precipitate formation and there is no smell produced.

The solution becomes basic due to formation of KOH.

The chemical signs for the reaction of Potassium with water are the change in temperature. There won't be any release of smell or color change with no precipitate formation.

The reaction of Potassium with water takes place with the release of energy. The energy released will be the characteristic of the exothermic reaction. The reaction thereby results in the change of the temperature.

The reaction produces KOH and hydrogen gas. The hydrogen gas has been colorless and odorless gas, thereby there will not be any smell or color change. Although the formation of KOH will also be in liquid, so no precipitate has been observed.

The chemical signs for the reaction of Potassium with water are the change in temperature. There won't be any release of smell or color change with no precipitate formation.

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the volume increases

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