the mass of 3 PB tablets was measured to be 3.1398 g. The tablets were crushed, and 2.9551 g of the powder was transferred to a beaker and reacted with HCl. After filtration, the filtrate was transferred to a 50-mL volumetric flask and diluted with water. 10.00 mL of this stock solution was combined with 0.2 M Na3PO4. The resulting precipitate weighed 0.2798 g after drying. The mass of BSS per tablet is

elements make up everything, and they combine to make compounds.

the answer is c

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