Objects will only change their motion (direction, speed) if there is an unbalanced force of some kind acting on them. Balanced forces result in no change in the object's state of motion.

5 0

2 years ago

Salicylic acid (C7H6O3) reacts with acetic anhydride (C4H6O3) to form acetylsalicylic acid (C9H8O4).

zavuch27 [327]

Answer : The correct option is, (B) Salicylic acid

Solution :

First we have to calculate the moles of salicylic acid and acetic anhydride.

$\text{Moles of }C_7H_6O_3=\frac{\text{Mass of }C_7H_6O_3}{\text{Molar mass of }C_7H_6O_3}=\frac{70g}{138.121g/mole}=0.507moles$

$\text{Moles of }C_4H_6O_3=\frac{\text{Mass of }C_4H_6O_3}{\text{Molar mass of }C_4H_6O_3}=\frac{80g}{102.09g/mole}=0.783moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

$2C_7H_6O_3(aq)+C_4H_6O_3(aq)\rightarrow 2C_9H_8O_4(aq)+H_2O(l)$

From the balanced reaction we conclude that

As, 2 moles of salicylic acid react with 1 mole of acetic anhydride

So, 0.507 moles of salicylic acid react with $\frac{0.507}{2}=0.2535$ mole of acetic anhydride

The excess of acetic anhydride = 0.783 - 0.2535 = 0.5295 moles

That means the in the given balanced reaction, salicylic acid is a limiting reagent because it limits the formation of products and acetic anhydride is an excess reagent.

Hence, the limiting reagent is, salicylic acid.

7 0

2 years ago