Pentru prepararea propenei se trataeaza alcoolul izopropilic, la cald cu 100g solutie de acid sulfuric 98%.Raportul de masa intre cantitatea initiala de apa si cea finala este de 1:28.Cantitatea de izopropanol supusa deshidratarii si concentratia acidului sulfuric la sfarsitul reactiei sunt: A:180g, 60% B:180g, 63,63% C:360g, 63,63% D:180kg, 63,63% E:173,33g, 63,63% Raspuns corect:B

FeCl₃  +  3NaOH  →  Fe(OH)₃  +  3NaCl​

Explanation:

You are given a skeleton equation, or unbalanced equation.

FeCl₃  +  NaOH  →  Fe(OH)₃  +  NaCl​

Count the number of atoms on each side. If there is 1 atom, the subscript is not written. If the subscript to the right of a bracket, it belongs to each element in the bracket.

Reactants     →       Products

Fe  1                        Fe  1

Cl   3                       Cl   1         Not balanced

Na  1                        Na  1

O   1                         O   3        Not balanced

H   1                         H   3        Not balanced

The number of each element must be the same in the reactants and products. We can see that Cl (chlorine), O (oxygen) and H (hydrogen) have different numbers.

Write in coefficients in front of formulas (separated by + sign). Coefficients multiply each subscript (or "1" if not written) in the formula. Recount the atoms until you have equal reactant and product atom numbers.

I see that I need more chlorine in my products. Multiply the formula that has "Cl" by 3.

FeCl₃  +  NaOH  →  Fe(OH)₃  +  3NaCl​

Reactants     →       Products

Fe  1                        Fe  1

Cl   3                       Cl   3          Cl is balanced now.

Na  1                        Na  3         Not balanced

O   1                         O   3         Not balanced

H   1                         H   3         Not balanced

Fix the "Na" now. Multiply the formula with "Na" on the left by 3.

FeCl₃  +  3NaOH  →  Fe(OH)₃  +  3NaCl​

Reactants     →       Products

Fe  1                        Fe  1

Cl   3                       Cl   3

Na  3                       Na  3

O   3                        O   3

H   3                        H   3

Each side has the same number of each element. Therefore, this is balanced now.

Balanced formula:

FeCl₃  +  3NaOH  →  Fe(OH)₃  +  3NaCl​