List of practice Questions

How many liters of milk can a hemispherical bowl of diameter 10.5 cm hold?

∆ABC is an isosceles triangle in which AB = AC. Side BA is produced to D such that AD = AB (see Fig. 7.34). Show that ∠ BCD is a right angle.

∆ABC is an isosceles triangle in which AB = AC.

A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1m, then find the volume of the iron used to make the tank.
The length of 40 leaves of a plant is measured correct to one millimeter and the obtained data is represented in the following table:

Length (in mm) 

Number of leaves

118 − 126 

3

127 − 135

5

   136 − 144    

9

145 − 153

12

154 − 162

5

163 − 171

4

 172 − 180

2


(i) Draw a histogram to represent the given data. 
(ii) Is there any other suitable graphical representation for the same data? 
(iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?

Find the volume of a sphere whose surface area is 154 cm2.
Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.
A dome of a building is in the form of a hemisphere. From inside, it was whitewashed at the cost of ₹4989.60. If the cost of whitewashing is ₹20 per square meter, find the
(i) inside surface area of the dome,
(ii) volume of the air inside the dome
ABC is a right angled triangle in which ∠A = 90° and AB = AC. Find ∠B and ∠C.
Twenty-seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S'. Find the 
(i) radius r' of the new sphere, 
(ii) ratio of S and S'
What is the physical state of water at— 
(a) 25°C 
(b) 0°C
(c) 100°C ?
Given below is the scientific name of Mango. Identify the correctly written name. 
Mangifera Indica
Mangifera indica
Define a taxon. Give some examples of taxa at different hierarchical levels.
What will be the conjugate bases for the Brönsted acids: HF, H2SO4 and HCO3–?
Write the conjugate acids for the following Brönsted bases: NH2–, NH3 and HCOO–.
Describe the effect of: 
  1. addition of H2
  2. addition of CH3OH
  3. removal of CO
  4. removal of CH3OH 

on the equilibrium of the reaction:
\(2H_2(g) + CO (g) ⇋ CH_3OH (g)\)

Can you identify the correct sequence of taxonomical categories?
(a) Species → Order → Phylum → Kingdom
(b) Genus → Species → Order → Kingdom
(c) Species → Genus → Order → Phylum
The species: H2O, HCO3–, HSO4– and NH3 can act both as Brönsted acids and bases. For each case give the corresponding conjugate acid and base.
Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in case of higher plants and animals on one hand, and bacteria on the other hand.
Classify the following species into Lewis acids and Lewis bases and show how these act as Lewis acid/base: (a) OH– (b) F– (c) H+ (d) BCl3
The concentration of hydrogen ions in a sample of soft drink is 3.8 × 10–3 M. What is its pH?
Define and understand the following terms: 
(i) Phylum 
(ii) Class 
(iii) Family 
(iv) Order
(v) Genus.
The pH of a sample of vinegar is 3.76. Calculate the concentration of hydrogen ions in it.
The ionization constant of HF, HCOOH and HCN at 298K are 6.8×10–4,1.8×10–4 and 4.8×10–9 respectively. Calculate the ionization constants of the corresponding conjugate base.
At 473 K, equilibrium constant Kc for decomposition of phosphorus pentachloride, PCl5 is \(8.3 ×10^{-3}\). If decomposition is depicted as,
\(PCl_5 (g) ⇋ PCl_3 (g) + Cl_2 (g)\)   \(∆_r H^Θ = 124.0\  kJ mol^{–1}\)
  1. write an expression for Kc for the reaction.
  2. what is the value of Kc for the reverse reaction at the same temperature?
  1. what would be the effect on Kc if
    1. more PCl5 is added
    2. pressure is increased
    3. the temperature is increased ?
The ionization constant of phenol is 1.0 × 10–10. What is the concentration of phenolate ion in a 0.05 M solution of phenol? What will be its degree of ionization if the solution is also 0.01M in sodium phenolate?