Which of the following are exothermic processes?
(i) Reaction of water with quicklime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor(crystals)

Calcium phosphate is present in tooth enamel.  Its nature is

Generally, non-metals are not lustrous. Which of the following nonmetal is lustrous?

Which of the first enzyme to mix with food in the digestive tract?

The substance that triggers the fall of mature leaves and fruits from plants is due to

The proper representation of series combination of cells obtaining maximum potential is

Choose the incorrect statement

Which of the following is not an example of a bio-mass energy source?

Structural formula of benzene is

Which of the following gives the correct increasing order of the atomic radii of O, F and N?

What is rust?

State one basic difference between a physical change and a chemical change.

Which gas is usually liberated when an acid reacts with a metal?

A compound ‘X’ is an important ingredient of an antacid. It is also used in fire extinguisher. Identify ‘X’.

What seems to happen when a piece of sodium metal is dropped into water?

Which gas is liberated when a metal reacts with an acid? How will you test the presence of this gas?

Name the metal which reacts with a very dilute HNO₃ to evolve hydrogen gas.

Name the term for transport of food from leaves other parts of the plant.

Name the excretory unit of a kidney

Name the tissue which transports water and mineral in a plant

What is a neuron?

Name one endocrine gland which performs dual function.

Name the part of hind brain which takes part in regulation of respiration.

What is the S.I. unit of electric potential?

Which has a higher resistance: a 50 W lamp bulb or a 25 W lamp bulb and how many times?

What is the S.I. unit of charge?

What is solenoid?

What are concentric circles?

Who discovered that mechanical motion can produce current?

Name the reaction responsible for large energy production in the sun.

What is the minimum speed of wind required by a wind mill to maintain the necessary speed of turbine in electric generator?

Name the gas which is the major constituent of bio gas?

Write the next homologue of each of the following:
(i) C₂H₄
(ii) C₄H₆

Write the two succeeding members of the following homologous series:
C₂H₆'C₃H₈

What is the difference between two consecutive members in a homologous series in alkanes in terms of:
(i) Molecular mass,
(ii) Number of atoms of elements.

Lithium, sodium and potassium form a Dobereiner's triad. The atomic masses of lithium and potassium are 7 and 39 respectively. Predict the atomic mass of sodium.

Why was the system of classification of elements into triads not found suitable? 

State modern periodic law of classification of elements.

Give a balanced equations for the following reactions:
(a) Combination reaction.
(b) Displacement reaction.
(c) Double displacement reaction.
(d) Redox reaction.
(e) Thermal decomposition reaction.

Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example, How will you test for the presence of the gas?

You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleansing the vessels.

Why is blood circulation in human heart called double circulation?

Give the difference between sensory and motor nerve.

An electric iron has a rating of 750 W, 220 V. Calculate
(i) current passing through it, and
(ii) its resistance, when in use

(a) What is the role of fuse, used in series with any electrical appliance?
(b) Why should a fuse with defined rating not be replaced by one with a larger rating?

Describe the areas where acids are most likely expected?

Give the electron dot structure of ethane.

The position of three elements A, B and C in the Periodic Table is shown below

Giving reasons, explain the following:
(a) Element A is a non-metal.
(b) Atom of element C has a larger size than atom of element A.
(c) Element B has a valency of 1.

Define the term decomposition reaction. Give one example each of thermal decomposition and electrolytic decomposition.

What happens when:
(i) Dilute hydrochloric acid is added to solid sodium carbonate.
(ii) Quicklime is treated with water.
(iii) Sodium chloride solution is added to lead nitrate solution.
Also write the chemical equation in each case.

A liquid has a pH less than 7 which represent all acidic solution:
(i) State the nature of the solution, if its pH increases from 7 to 14.
(ii) Mention the ion whose concentration increases with the increase in pH value.
(iii) Suggest a method that is generally used for measuring the pH value.

While eating food, you happen to spill some curry on your white shirt. You immediately scrub it with soap. What happens to its yellow color on scrubbing with soap? Why? What happens to this stain when the shirt is washed with plenty of water?

(a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides?
Na₂O, ZnO, Al₂O₃, CO₂, H₂O.
(b) Why is it that non-metals do not displace hydrogen from dilute acids?

(a) Arrange the following metals in the order of their decreasing activities: Aluminium, Gold, Sodium, Copper
(b) Give chemical equation for the reaction of aluminium powder with manganese dioxide on heating.

What is 'translocation'? Why is it essential for plants?Where in plants are the following synthesized:
(i)Sugar  (ii)Hormones

Name the constituents of blood.Why white blood corpuscles are called 'soldiers of the body'?

Describe the central nervous system in human being under the following heads:
(i) Regions included
(ii) Three functions of any one region

Draw a diagram showing endocrine glands in a male body. Label the following glands on it:
(i) Pituitary
(ii) Thyroid
(iii) Adrenal
(iv) Testes

(i) Draw a schematic diagram of a circuit consisting of a battery of five 2 V cells, a 5 Ohm resistor, a 10 Ohm resistor and a 15 Ohm resistor, and a plug key, all connected in series.
(ii) Calculate the electric current passing through the above circuit when the key is closed.

Differentiate between ammeter and voltmeter.

(a) What are 'magnetic field lines'? How is the direction of a magnetic field at a point determined?
 (b) List any three properties of magnetic field lines.
 (c) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.

Distinguish between an electric motor and generator?

(a) What is a 'solar cell'?
(b) Why is biogas considered an ideal fuel for domestic use?
(c) Name a device in which controlled chain reaction is used.

(a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity required to obtain useful energy with a windmill?
(c) Define the term 'nuclear fission'.

What happens when a piece of
(a) Zinc metal is added to copper sulphate solution?
(b) Aluminium metal is added to dilute hydrochloric acid?
(c) Silver metal is added to copper sulphate solution? Write the balanced chemical equation if the reaction occurs.

(a) Why is sulphuric acid called 'King of Chemicals'?

(b) Describe the three chemical reactions that take place during the conversion of sulphur dioxide to sulphuric acid in the 'Contact Process'.

(c) Why should water be never added drop wise to concentrated sulphuric acid?

An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.

Describe the alimentary canal of man.

Name various plant hormones. Also give their physiological effects on plant growth and development.

Find out the following in the electric circuit given in Figure
(a) Effective resistance of two 8 \(\Omega\) resistors in the combination
(b)Current flowing through 4 \(\Omega\) resistor
(c) Potential difference across 8 \(\Omega\) resistance
(d) Power dissipated in 4 \(\Omega\) resistor
(e) Difference in ammeter readings, if any.

(a) What is an electromagnet? What does it consist of?
(b) Name one material in each case which is used to make a
(i) Permanent magnet
(ii) Temporary magnet
(c) Describe an activity to show how you can make an electromagnet in your school laboratory.

(i) Distinguish between renewable and non-renewable sources of energy giving one example of each.
(ii) Why is the use of wood as a fuel not advised although forests can be replenished?

A compound C (molecular formula, C₂H₄O₂) reacts with Na - metal to form a compound R and evolves a gas which burns with a pop sound. Compound C on treatment with an alcohol A in presence of an acid forms a sweet smelling compound S (molecular formula, C₃H₆O₂). On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A. Identify C, R, A, S and write down the reactions involved.

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but different number of electrons in their outermost shells. It was found that elements A and G combine to form an ionic compound which can also be extracted from sea water. Oxides of the elements A and B are basic in nature while those of E and F are acidic. The oxide of element D is almost neutral. Answer the following questions based on the information given herein:
(i) To which group period of the Periodic table do the listed elements belong?
(ii) Which one of the eight elements is likely to be a noble gas?
(iii) Which one of the eight elements would have the largest atomic radius?
(iv) Which two elements amongst these are likely to be non-metals?
(v) Which one of these eight elements is likely to be a semi-metal or metalloid?