Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is

$\frac{\sqrt{3}}{\sqrt{2}}$

$\frac{4 \sqrt{3}}{3 \sqrt{2}}$

1/2

$\frac{3 \sqrt{3}}{4 \sqrt{2}}$

Solution

$\frac{3 \sqrt{3}}{4 \sqrt{2}}$

For bcc lattice: Z = 2, a = $\frac{4 r}{\sqrt{3}}$

For fcc lattice: Z = 4, a = $2 \sqrt{2 r}$

$∴ \frac{d_{25^{0} C}}{d_{900^{o} C}} = \frac{{(\frac{Z M}{N_{A} a^{3}})}_{b c c}}{{(\frac{Z M}{N_{A} a^{3}})}_{f c c}} = \frac{2}{4} {(\frac{2 \sqrt{2 r}}{\frac{4 r}{\sqrt{3}}})}^{3} = \frac{3 \sqrt{3}}{4 \sqrt{2}}$

Some More Questions From The Solid State Chapter

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Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

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The Solid State

Some More Questions From The Solid State Chapter

Why do solids have a definite volume?

Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Why is glass considred a super-cooled liquid?

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show clevage property?

Classify the following solids in different categories based on the nature of intermolecular forces operating in them:
Potassium sulphate, tin, benzene, urea, ammonia, water, zinc
sulphate, graphite, rubidium, argon, silicon carbide.

Solid A is a very hard, electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

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The Solid State

Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is 32 4332 1/2 3342

Some More Questions From The Solid State Chapter

Why do solids have a definite volume?

Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Why is glass considred a super-cooled liquid?

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show clevage property?

Classify the following solids in different categories based on the nature of intermolecular forces operating in them: Potassium sulphate, tin, benzene, urea, ammonia, water, zinc sulphate, graphite, rubidium, argon, silicon carbide.

Solid A is a very hard, electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

Ionic solids conduct electricity in liquid state but not in solid state. Explain.

What type of solids are electrical conductors, malleable and ductile?

Give the significance of a 'lattice point'.

Name the parameters that characterize a unit cell.

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Classify the following solids in different categories based on the nature of intermolecular forces operating in them:
Potassium sulphate, tin, benzene, urea, ammonia, water, zinc
sulphate, graphite, rubidium, argon, silicon carbide.