Question

(3) How many grams of HCl reacts with 8.7 gram of MnO2?
MnO2 + 4HCL
MnCl2 + 2H20
(atomic mass of Mn = 55,0 = 16, Cl= 35.5)
a 1.46 g b) 14.6 g c) 7.3 g d) 3.65 g​

Answer 1

Answer:

• Option (b) - 14.6 g

Chemical reaction of HCl and MnO₂ is given as,

⇒ MnO₂ + 4HCl ➞ MnCl₂ + 2H₂O

According to the question, we have to find how many grams of HCl will react with 8.7g of MnO₂?

Clearly, from the chemical reaction, 4 mole of HCl will react with 1 mole of MnO₂ to give 1 mole MnCl₂ and 2 mole H₂O.

Given that,

Atomic Mass:

• Mn = 55 g/mol
• O = 16 g/mol
• Cl = 35.5 g/mol

According to the question,

• Mass of MnO₂ = 8.7g

Let's find the molecular mass of the compound first before finding the mole:

⇒ Molecular mass = Mn + 2 × O

⇒ Molecular mass = 55 + 2 × 16

⇒ Molecular mass = 55 + 32

⇒ Molecular mass = 87 g/mol

Now, Let's find the number of mole of MnO₂

⇒ No. of mole = Mass given / Molar mass

⇒ No. of mole = 8.7 / 87

⇒ No. of mole = 0.1 mole

But, from the chemical reaction we found that,

⇒ 1 mole MnO₂ reacts with 4 mole HCl

So,

⇒ 1/10 mole MnO₂ reacts with 4/10 mole HCL

We found the number of mole of HCl required to be 4/10 = 0.4 mole

As discussed above,

⇒ Number of mole = Mass given / Molar mass

⇒ 0.4 = mass / ( H + Cl )

⇒ 0.4 ( 1 + 35.5 ) = mass

• Atomic mass of H = 1 g/mol
• Atomic mass of Cl = 35.5 g/mol

⇒ 0.4 (36.5) = mass

⇒ Mass required = 14.6g

Hence, 14.6g of HCl will react with 8.7g of MnO₂.

∴ Option (B) is correct.

Answer 2

$\Large{\textsf{\textbf{\underline{\underline{Given\::}}}}}$

A balanced chemical reaction :

$\red\star\:\bf{MnO_2~+~4 HCl~\rightarrow~MnCl_2\:+\:Cl_2\:+\:2 H_2O\:}$

$\Large{\textsf{\textbf{\underline{\underline{To\:do\::}}}}}$

• No. of grams of HCl reacts with 8.7 grams of MnO₂.

$\Large{\textsf{\textbf{\underline{\underline{Solution\::}}}}}$

From the above balanced chemical reaction,

➠ 1 mole of MnO₂ reacts with 4 moles of HCl.

As we know that,

$\orange\bigstar\:{\Large\mid}\:\bf\purple{Mole\:=\:\dfrac{Given\:Mass}{Molecular\:Mass}\:}\:{\Large\mid}\:\green\bigstar$

✯ Molecular mass of MnO₂ is,

➣ 55 + 32

➣ 87 grams/mole

✯ Molecular mass of HCl is,

➣ 1 + 35.5

➣ 36.5 grams/mole

Now,

For MnO₂ :

• Given mass = 8.7 grams

• Molecular mass = 87 grams/mole

$:\implies\:\tt{ Mole~ of~ MnO_2~\:=\:\dfrac{8.7}{87}\:}$

$:\implies\:\tt{ 1~ mole~ of~ MnO_2~\:=\:0.1\:mol}$

For HCl :

Let,

• Given mass = x

• Molecular mass = 36.5 grams/mole

• No. of Moles of HCl is 4 mol.

$:\implies\:\tt{ Mole~ of~ HCl~\:=\:\dfrac{x}{36.5}\:}$

$:\implies\:\tt{ 4~\:=\:\dfrac{x}{36.5}\:}$

$:\implies\:\tt{ x~\:=\:4\times{36.5}\:}$

$:\implies\:{\textsf{\textbf{\pink{ x~\:=\:14.6\:grams\:}}}}$

∴ b) 14.6 grams of HCl is reacted.