CBSE Class 10 - Science - CH2 - Acids, Bases and Salts

Acids, Bases and Salts

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MCQs, NCERT Solutions, Q & A

Q1: The most commonly used indicator in laboratory is
(a) Methyl Orange
(b) Litmus
(c) Phenolphtalein
(d) Universal Indicator

Answer:  Universal Indicator



Q2: Olfactory indicators are:
(a) Clove
(b) Turmeric
(c) Soap
(d) Rose Petals

Answer: (a) Clove

CBSE - Class 8 - Maths - Cubes and Cube Roots

Important Points 
& NCERT Solutions

1. If n is a perfect cube then n = m³ or m is the cube root of n. i.e. (n = m × m × m) 

2. A cube root is written as ∛n or n^1/3.

3. ∛2, ∛3, ∛4 etc. all are irrational numbers.

4. The cube root of negative perfect cube is negative. i.e.

    (-x)³=  -x³ 

CBSE - Class 9 - CH2 - Is Matter Around Us Pure

Q1: On the basis of composition, how matter is classified?

Answer:

• Pure Subtance
• Mixture

Q2(NCERT): What is meant by a pure substance?

Answer: A sample of matter containing only one substance is called a pure substance. In other words all constituents of the substance are same in their chemical nature.

SYNONYMS (Quiz)

SYNONYMS

Each of the following consists of a word in capital letters followed by four words or groups of words. Select the words or group of words that is most similar in meaning to the word in capital letters.
(Taken from various competitive examinations like NDA, CDS, University graduate entrance, TET ...)

1. GENIAL
(a) Generous
(b) Wonderful
(c) Liberal
(d) Friendly and cheerful

CBSE - Class 9 - Social Science SA1 Paper (2011)

Class 9- Social Science - SA1 - Paper

CBSE Class 9 English (C) - Unit 4 - MODALS

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Unit 4 - MODALS

A. Ability

1. What are the ten different ways in which you can use a ruler other than its regular use? List your answer below.

     e.g. You can use it to dig holes.

Answer:

Watch Wonders of The World

Google initiated a new education project called the World Wonders Project. It offers various monumental sites of historical, architectural and natural interest. It includes monuments, memorials, cathedrals, castles, landscapes.

Along with a 3D street view, there is ample information available to enrich your knowledge. The only caveat is, currently no Indian site is covered. Hope we shall see it very soon.

CBSE Class 9- CH5: Introduction to Euclid's Geometry

Fragment of Euclid's Elements
source: wikicommons

NCERT Chapter Solutions
and Other Q & A

Exercise 5.1

Q1: Which of the following statements are true and which are false? Give reasons for your answers.

(i) Only one line can pass through a single point.

(ii) There are an infinite number of lines which pass through two distinct points.

(iii) A terminated line can be produced indefinitely on both the sides.

(iv) If two circles are equal, then their radii are equal.

(v) As shown in Fig. below, if AB = PQ and PQ = XY, then AB = XY.

Answer:

Plurals with Different Meanings

Some Nouns have same meaning in singular form but have different meanings in plural form.

A few are listed here:

Colours:

1. Hues
2. Regiment (unit of army)

 Compasses:

1. Magnetic compasses used for navigation
2. Instruments used in geometry

How to learn naming Chemical Formulae?

Chemicals
(src:deviantart)

Nomenclature of Simple Inorganic compounds.

1. A formula is a shorthand notation used to identify the composition of a molecule or compound.

2. For example chemical formula of water is H₂O. It includes the symbol of each element (e.g. Hydrogen:H and Oxygen:O)  in the molecule, along with numerical subscripts to show how many atoms of each element are present.

3. Most of the inorganic compounds are binary compounds i.e. it consists of two elements. Some are ternary i.e. contain more than two elements.