Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?
(i) It is an endothermic reaction
(ii) It is an exothermic reaction
(iii) The pH of the resulting solution will be more than seven
((iv) The pH of the resulting solution will be less than seven

Which of the following is not a mineral acid?

Which one of the following properties is not generally exhibited by ionic compounds?

The correct sequence of anaerobic reactions in yeast is

Involuntary actions in the body are controlled by

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be

A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in the figure. The direction of the magnetic field at a point will be North to South

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

Which of the following is the correct representation of electron dot structure of nitrogen?

Which of the given elements A, B, C, D and E with atomic number 2,3, 7, 10 and 30 respectively belong to the same period?

Name the gas evolved when zinc reacts with dil.HCl.

What is rust?

Silver articles develop black coating and copper articles develop green coating. Which chemical phenomenon is responsible for this coating?

What is the effect of an increase in the concentration of H⁺ ions? 1M HCl or 1M CH₃COOH.

Name a reducing agent that may be used to obtain manganese from manganese dioxide.

Name one metal and non-metal which exists in liquid state at room temperature?

Give an example of a metal which is the best conductor of heat.

What is meant by 'translocation' with respect to transport in plants?

What are the two functions of the kidneys?

What is the impact of leakage or loss of blood upon the pressure?

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

Name the hormone secreted by thyroid gland.

Write the components of peripheral nervous system.

How is ammeter and voltmeter connected in a circuit?

What is the advantage of the third wire of earth connection in domestic electric appliances?

Should the heating element of an electric iron be made of iron, silver or nichrome wire?

What constitutes the field of a magnet?

What is electric generator?

On what basis a generator works?

Which one of the following is a renewable resource?
Natural gas, Petrroleum, Ground water, Coal

What is energy?

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

Draw the structure of ethanol molecule.

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

Name a functional group present in 
(i) CH₃CHO
(ii) C₂H₅COOH

Chlorine, bromine and iodine form a Dobereiner's triad. The atomic masses of chlorine and iodine are 35.5 and 126.9 respectively. Predict the atomic mass of bromine.

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

How many vertical columns are there in the modern periodic table and what are they called?

Balance the following chemical equations and identify the type of chemical reaction.
(a) Mg(s) + Cl₂(g) \(\rightarrow\) MgCl₂(s)
(b) HgO(s) \(\overset {Heat}{\rightarrow}\) Hg(l) + O₂(g)
(c) Na(s) + S(s) \(\rightarrow\) Na₂S(s)
(d) TiCl₄(l) + Mg(s) \(\rightarrow\) Ti(s) + MgCl₂
(e) CaO(s) + SiO₂(s) \(\rightarrow\) CaSiO₃(s)
(f) H₂O₂(l) \(\overset{uv}{\rightarrow}\) H₂O(l) + O₂(g)

Under what soil condition do you think a farmer would treat the soil of his fields with quicklime (calcium oxide) or slaked lime (calcium hydroxide ) or chalk (calcium carbonate) ?

Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H₂SO₄.

Plants have low energy needs as compared to animals.Explain

(a) Draw labelled diagram of human brain.
(b) What is the function of mid brain?
(c) Name the three different parts of hind brain and give one function of each.

Why is parallel arrangement used in domestic wiring?

Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor ?

Mention any two limitations of using fossil fuels.

What change will you observe if you test soap with litmus paper (red and blue)?

How could modern periodic table remove the anomalies of Mendeleev's periodic table?

When a copper wire was left in silver nitrate solution for sometime, it was observed that the solution turned bluish green.
(i) Explain the observation.
(ii) Write the balanced chemical equation to represent the change taking place.

(a) Write chemical equations.
(i) When carbon dioxide gas is passed through lime water.
(ii)When excess of carbon dioxide gas is passed through lime water.
(b) List two natural forms of calcium carbonate.

(a) Write the chemical name and formula of bleaching powder.
(b) Why does bleaching powder smell of chlorine when exposed to air?
(c) Write chemical equation to represent the action of dilute hydrochloric acid on bleaching powder

Name the acid present in the following:
(i) Tomato, (ii) Vinegar, (iii) Tamarind

State reason for the following:
(i) Non-metals cannot displace hydrogen from the acids.
(ii) Hydrogen is not a metal, yet it is placed in the activity series of metals.
(iii) Aluminium is more reactive than iron, yet its corrosion is less than that of iron

(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'?

What are hormones? State one function of each of the following hormone
(i) Thyroxin
(ii) Insulin.

Write down three main differences between auxin and cytokinin.

(a) What is meant by 'Electric Resistance' of a conductor?
(b) A wire of length 'L' and resistance 'R' is stretched so that its length is doubled and the area of cross-section is halved. How will its:
(i) resistance change
(ii) resistivity change

(a) State Ohm's Law.
(b) Draw a schematic diagram of the circuit for studying Ohm's Law.

(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) Why is the Solar Cooker box covered with a plane glass plate?
(b) Why is energy of water flowering in a river considered to be an indirect form of solar energy?
(c) How is the fission of nucleus brought about?

On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of aqueous solution of the gas X?

Account for the following:
(i) State the relation between hydrogen ion concentration of an aqueous solution and its pH.
(ii) An aqueous solution has a pH value of 7.0. Is this solution acidic, basic or neutral?
(iii) Which has a higher pH value, 1MHCl or 1MNaOH solution?
(iv) Tooth enamel is one of the hardest substances in our body. How does it undergo damage due to eating chocolates and sweets? What should we do to prevent it?
(v)How do [H⁺] ions exist in water?

Two ores A and B were taken. On heating ore A gives CO₂ whereas, ore B gives SO₂ .What steps will you take to convert them into metals?

How do carbohydrates, proteins and fats get digested in human beings?

Draw and explain the structure of a neuron and explain its function.

How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?

(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.

Energy from various sources is considered to have been derived from the sun. do you agree? Justify your answer.

a) Write the formula and draw electron dot structure of carbon tetrachloride?
b) What is saponification? Write the reaction involved in this process.

Explain the trends in the modern Periodic Table of various properties like valency, atomic size, metallic and non-metalic properties of the atoms of elements.