Question

find magnitude of charge present on 4.8 milligram of SO4²-​

Answer 1

Answer:

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Molar mass of Mg+2=24g

Given mass of Mg+2=48g

No. of moles of Mg+2=Molar massGiven mass=2448=2 moles

1 mole of Mg+2 = 2 moles of electrons

∴2 moles of Mg+2 = 4 moles of electrons

∴ No. of electrons = no. of moles of electrons × Avogadro's constant

⇒ No. of electrons =4×6.023×1023=2.4×1024

As we know that,

Charge on 1 electron =1.6×10−19C

∴ Total charge on 48 g Mg+2=no. of e−s×charge on 1 e−=(2.4×1024)×(1.6×10−19)=3.84×105C≈3.86×105C

Hence, the correct answer is 3.86×105C

Answer 2

Answer:

$\huge \sf\blue{\colorbox{pink}{Answer}}$

Molar mass of Mg+2=24g

Given mass of Mg+2=48g

No. of moles of Mg+2=Molar massGiven mass=2448=2 moles

1 mole of Mg+2 = 2 moles of electrons

∴2 moles of Mg+2 = 4 moles of electrons

∴ No. of electrons = no. of moles of electrons × Avogadro's constant

⇒ No. of electrons =4×6.023×1023=2.4×1024

As we know that,

Charge on 1 electron =1.6×10−19C

∴ Total charge on 48 g Mg+2=no. of e−s×charge on 1 e−=(2.4×1024)×(1.6×10−19)=3.84×105C≈3.86×105C

Hence, the correct answer is 3.86×105C