cho A g hỗn hợp bột nhôm sắt vào sắt dd NaOH dư thấy còn lại 2,8g chất rắn không tan. Nếu cho hỗn hợp vào dd H2So4 dư thấy thoát ra 4,48g lít khí đktc và thu đc dung dịch X xác định giá trị a tìm khối lượng muối có trong X

i believe the answer is true.

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