Identify the following solutions, whether they are acidic or alkali. Solution Change in indicator Acid/ Base Litmus Phenolphthalein Methyl orange 1. ___ No change ___ 2. ___ ___ Orange colour turns red 3. Red litmus blue ___ ____

Phenolphthalein and methyl orange are synthetic indicators and the litmus indicator is a natural indicator obtained from lichens. They show different observations in acidic or basic solutions. Therefore, the given table can be completed as, Solution Change in indicator Acid/ Base Litmus Phenolphthalein Methyl orange 1. Blue litmus red No change Orange colour turns red Acid 2. Blue litmus red No change Orange colour turns red Acid 3. Red litmus blue Pink Yellow Base

E M B I B E

General Science>Chapter 12 - Introduction to Acid & Base>Exercises>Q 9

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IMPORTANT

Earn 100

Classify the following substances into acidic, basic and neutral groups -

$HCl, NaCl, MgO, KCl, CaO, H_{2} {SO}_{4}, {HNO}_{3}, H_{2} O, {Na}_{2} {CO}_{3}$ .

Important Questions on Introduction to Acid & Base

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8th Maharashtra Board

IMPORTANT

General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 1

We consume many food items in our daily life e.g. lemon, tamarind, tomato, sugar, vinegar, salt etc. Do all items taste similar?

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8th Maharashtra Board

IMPORTANT

General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 2

Write the taste of lemon, sugar, curd, lime, baking soda, amla, tamarind, raw mango, pomegranate, water (sour, astringent, sweet, bitter, tasteless)

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8th Maharashtra Board

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General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 1

What happens when sour substances like lime juice, tamarind water falls on shahabad stones or kitchen platform? Why?

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8th Maharashtra Board

IMPORTANT

General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 2

How can we say that the soil samples collected from your surroundings are acidic, alkaline or neutral?

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8th Maharashtra Board

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General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 3

Which substances are used to clean greenish stains on copper vessels and to shine blackish silver utensils?

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8th Maharashtra Board

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General Science>Chapter 12 - Introduction to Acid & Base>Can you tell?>Q 4

Why tooth-paste is used for brushing teeth?

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8th Maharashtra Board

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General Science>Chapter 12 - Introduction to Acid & Base>Use your brain power

The iron knife shines better after cutting the sour fruits like lemon, raw mangoes. Why?

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8th Maharashtra Board

IMPORTANT

General Science>Chapter 12 - Introduction to Acid & Base>Exercises>Q 1

Identify the following solutions, whether they are acidic or alkali.

Solution	Change in indicator			Acid/ Base
Solution	Litmus	Phenolphthalein	Methyl orange	Acid/ Base
1.	___	No change	___
2.	___	___	Orange colour turns red
3.	Red litmus blue	___	____