Question

how many moles of Na+ are present in 250ml 0.05M Na2So4​

Answer 1

Answer:

We usually talk about a solution so, let me rephrase your question. How many ions of Na+ and Cl- are present in a solution in which 1 mole of NaCl is completely dissolved in water?

First, NaCl is very soluble in water.

Solid NaCl dissociates completely into ions of Na+ and Cl- when forming an aqueous solution. This is written:

1 NaCl (s) → 1 Na+ (aq) + 1 Cl- (aq)

There are two moles of ions (one sodium and one chloride) on the product side. A mole is Avagadro’s number.

2 moles x 6.02 x 10^23 ions/mole = 1.2 x 10^24 ions.

Explanation:

Answer 2

Number of moles of ${Na}^{ + }$ are 0.025.

Given - Volume and molarity

Find - Number of moles

Solution - The dissociation of $Na_{2} SO_{4}$ results in production of 2 ${Na}^{ + }$ ions and 2 ${SO_{4}}^{2 - }$ ions.

So, 1 mole of $Na_{2} SO_{4}$ gives 2 moles of ${Na}^{ + }$ ions.

Calculating number of moles in given amount -

Number of moles = (250÷1000)×0.05×2

Solving bracket by performing division to find number of moles

Number of moles = 0.25×0.05×2

Performing multiplication to find number of moles

Number of moles = 0.025

Hence, the number of moles are 0.025.

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