Question

0.3 gram of an acid is neutralized by 40 cm cube of 0.5 normal NaOH equivalent mass of acid is

Answer 1

From the molarity of sodium hydroxide which is 0.5M, we can get the reacting moles.

Molarity 0.5moles / 1000cm³

Moles in 40cm³ are :

40/1000 × 0.5 = 0.02 moles.

Molarity mass of NAOH is 40

Moles = mass / molar mass

Mass = molar mass × moles

40 × 0.02 moles = 0.8 g

The reacting mass of Sodium hydroxide is 0.8 g

Lets take the mole ratio of acid to sodium hydroxide as 1 : 2 since the mass of the acid is almost half of the sodium hydroxide.

The reacting moles of the acid is thus :

0.02 / 2 = 0.01moles.

Given the molar mass of the acid as 0.3g, we can get the reacting mass since we have the moles.

Reacting mass is :

0.01 × 0.3 = 0.003g

Answer 2

Answer:

60

Explanation:

40$cm^{3}$ of 0.125 N NaOH corresponds to   $\frac{40}{1000} *0.125=0.005$

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×

0.005 g eq of NaOH will neutralise 0.005 g eq of acid.

Equivalent mass of acid =  

number of gram equivalents

-------------------------------------------

mass  

Equivalent mass of acid =  0.005 g eq

                                           ------------------

                                                  0.3 g

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Equivalent mass of acid = 60 g/eq.

Hence, the equivalent mass of the acid is 60 g/eq.