
The number of unit cells in 58.5g of NaCl is nearly
(A) $6\times {{10}^{22}}$
(B) $3\times {{10}^{22}}$
(c) $1.5\times {{10}^{23}}$
(D )$0.5\times {{10}^{24}}$
Answer
486k+ views
Hint: Avogadro’s constant is a physical value. Mole concept is used to tell the amount of substance.Molar mass of a substance is the sum of individual atomic masses of the atoms.
Complete answer:
Mole concept is a convenient way of expressing the amount of substance.According to mole concept, One mole of any compound has $6.022\times {{10}^{23}}$atoms/molecules/ions. This quantity is known as Avogadro’s constant, and denoted with ${{N}_{A}}$.
So, for the given compound, we have 58.5g of NaCl, and the molar mass of NaCl is 58.5g/mol. So, mole will be,
\[mole=\dfrac{weight}{mol.weight}\]
\[mole=\dfrac{58.5}{58.5}\]
therefore, mole of NaCl = 1.
So, for the given question there is one mole of NaCl, now we have to tell the number of unit cells in 58.5g of NaCl. So, according to Avogadro’s constant, in one mole of substance, there will be $6.022\times {{10}^{23}}$ unit cells.
NaCl has a rock salt type of structure. It is having FCC lattice. The atoms are present at the corners and at the face centres of the lattice with the ions of the opposite type occupying the alternate positions in between them. Therefore, in FCC lattice arrangement, there are 4 atoms in a cell. So, one mole have $6.022\times {{10}^{23}}$ unit cells of NaCl lattice.
So, the correct answer is “Option A”.
Note: The number of moles of a substance can be calculated by various means,these are, number of moles of molecules,number of moles of atoms,number of moles of gases (standard molar volume at STP=22.4Litre), number of moles of particles(molecules,atoms,ions),mole fraction.
Complete answer:
Mole concept is a convenient way of expressing the amount of substance.According to mole concept, One mole of any compound has $6.022\times {{10}^{23}}$atoms/molecules/ions. This quantity is known as Avogadro’s constant, and denoted with ${{N}_{A}}$.
So, for the given compound, we have 58.5g of NaCl, and the molar mass of NaCl is 58.5g/mol. So, mole will be,
\[mole=\dfrac{weight}{mol.weight}\]
\[mole=\dfrac{58.5}{58.5}\]
therefore, mole of NaCl = 1.
So, for the given question there is one mole of NaCl, now we have to tell the number of unit cells in 58.5g of NaCl. So, according to Avogadro’s constant, in one mole of substance, there will be $6.022\times {{10}^{23}}$ unit cells.
NaCl has a rock salt type of structure. It is having FCC lattice. The atoms are present at the corners and at the face centres of the lattice with the ions of the opposite type occupying the alternate positions in between them. Therefore, in FCC lattice arrangement, there are 4 atoms in a cell. So, one mole have $6.022\times {{10}^{23}}$ unit cells of NaCl lattice.
So, the correct answer is “Option A”.
Note: The number of moles of a substance can be calculated by various means,these are, number of moles of molecules,number of moles of atoms,number of moles of gases (standard molar volume at STP=22.4Litre), number of moles of particles(molecules,atoms,ions),mole fraction.
Recently Updated Pages
Master Class 12 Economics: Engaging Questions & Answers for Success

Master Class 12 Maths: Engaging Questions & Answers for Success

Master Class 12 Biology: Engaging Questions & Answers for Success

Master Class 12 Physics: Engaging Questions & Answers for Success

Master Class 12 Business Studies: Engaging Questions & Answers for Success

Master Class 12 English: Engaging Questions & Answers for Success

Trending doubts
Which are the Top 10 Largest Countries of the World?

Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE

What is a transformer Explain the principle construction class 12 physics CBSE

Who is Mukesh What is his dream Why does it look like class 12 english CBSE

Draw a labelled sketch of the human eye class 12 physics CBSE

What are the major means of transport Explain each class 12 social science CBSE
