An article about half-lives describes a daughter isotope. what is a daughter isotope?
a. the isotope that forms from the radioactive decay of a less stable isotope
b. the isotope that forms from the radioactive decay of a more stable isotope
c. an isotope that undergoes radioactive decay to form a less stable isotope
d. an isotope that undergoes radioactive decay to form a more stable isotope

The correct option is A.

Explanation:

A radioactive decay is defined as the decay process, in which a less stable nuclei decomposes to form a stable nuclei. The isotope which is less stable is the parent isotope and the more stable isotope is the daughter nuclei.

Hence, the correct option is A, the isotope that is formed from the radioactive decay of a less stable isotope.

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