7TH STANDARD SCIENCE. CHAPTER: 2. ACIDS AND BASES. LECTURE 5.

7TH STANDARD SCIENCE.

CHAPTER: 2. ACIDS AND BASES.

LECTURE 5.

...HI STUDENTS...

IN THIS VIDEO YOU WILL LEARN ABOUT THE 

THE FOLLOWING.

1. WHAT ARE ACIDIC AND BASIC NATURE?
2. NAMES OF SOME  MATERIALS AND THE NAME OF THE ACID OR BASE PRESENT IN THEM.
3. LITMUS PAPER.
4. WHAT ARE LIME AND LEMON WATER? AND PREPARATION O\F THEM.
5. LAB ACTIVITY WITH MAGNESIUM RIBBON.

1. WHAT ARE ACIDIC AND BASIC NATURE?

THE NATURE OF THE MATERIALS BASED ON THEIR TASTE THEY ARE CLASSIFIED AS ACIDS AND BASES.

SOME MATERIALS ARE SOUR IN TASTE AND BURNING IN SENSATION ARE SUSPECTED THE PRESENCE OF ACIDS UNTIL THEY ARE TESTED AND CONFIRMED AS ACIDS.  SO HERE YOU CAN UNDERSTAND THERE ARE SOME CONFIRMATION TESTS FOR ACIDS. AT IN THE SAME WAY SOME MATERIALS ARE BITTER IN TASTE AND SOAPY TO TOUCH ARE SUSPECTED THE PRESENCE OF BASES UNTIL THEY ARE TESTED AND CONFIRMED AS BASES. SO HERE ALSO WE CAN UNDERSTAND THERE ARE SOME CONFIRMATION TESTS FOR BASES.

2. NAMES OF SOME  MATERIALS AND THE NAME OF THE ACID OR BASE PRESENT IN THEM.

ACIDS:

• ACETIC ACID ----------VINEGAR
• CITRIC ACID------------LEMON AND ORANGE
• BUTYRIC ACID---------STALE CHEESE
• LACTIC ACID-----------MILK, CURD
• OXALIC ACID----------TOMATO, SPINACH
• MALIC ACID------------APPLE
• TANNIC ACID-----------TEA
• OLEIC ACID-------------OLIVE OIL
• STEARIC ACID---------FATS
• TARTARIC ACID-------GRAPES, TAMARIND
• PALMTIC ACID---------PALM OIL
• ASCARBIC ACID-------AMLA (EMBLICA FRUIT)
• URIC ACID---------------URINE

BASES:

• LIME WATER----------------CALCIUM HYDROXIDE
• GLASS CLEANER----------AMMONIUM HYDROXIDE
• SOAPS-------------------------SODIUM HYDROXIDE/POTASSIUM HYDROXIDE
• MILK OF MAGNESIUM---MAGNESIUM HYDROXIDE 

3. WHAT IS LITMUS PAPER?

LITMUS PAPER IS AN ARTIFICIAL INDICATOR WHICH CAN BE USED TO TEST THE PRESENCE OF ACID OR BASE IN ANY GIVEN MATERIAL.

LITMUS PAPER IS OF TWO TYPES 

1. BLUE LITMUS PAPER
2. RED LITMUS PAPER

WHEN A BLUE LITMUS PAPER CHANGES ITS COLOR INTO RED WITH ANY SUBSTANCE THAT SUBSTANCE IS CONFIRMED PRESENCE OF ACID.

WHEN A RED LITMUS PAPER CHANGES ITS COLOR INTO BLUE WITH ANY SUBSTANCE THAT SUBSTANCE IS CONFIRMED PRESENCE OF BASE.

4. WHAT ARE LIME AND LEMON WATER?

LIME WATER IS AS FOLLOWS....

PREPARATION OF LIME WATER

TAKE HALF A BEAKER FULL OF WATER. ADD ABOUT 5 GM OF LIME THAT WE APPLY TO BETEL LEAVES. STIR THE BEAKER WELL AND LET IT STAND OVERNIGHT. FILTER THIS SOLUTION THE FOLLOWING DAY. USE THIS FILTRATE IN ALL EXPERIMENTS YOU PERFORM. THIS SOLUTION SHOULD BE TRANSPARENT. THE SUBSTANCES THAT TURN BLUE LITMUS TO RED ARE ACIDIC IN NATURE. THE SUBSTANCES THAT ARE SOAPY TO TOUCH AND TURN RED LITMUS TO BLUE ARE BASIC IN NATURE. SOME OF THE SUBSTANCES GIVEN IN THE LIST DID NOT CHANGE THE COLOR OF EITHER BLUE OR RED LITMUS. THESE ARE SAID TO BE NEUTRAL IN NATURE.

LEMON WARE IS WATER MIXED WITH LEMON JUICE AS SIMPLE AS THAT.

5. LAB ACTIVITY WITH MAGNESIUM RIBBON.

BURN A SMALL PIECE OF MAGNESIUM RIBBON BY HOLDING IT WITH TONGS. COLLECT THE WHITE ASH AND DISSOLVE IT IN A LITTLE WATER. TOUCH THE SOLUTIONS FORMED AND TEST THIS

OXIDES OF MAGNESIUM WHEN DISSOLVED IN WATER FORM MAGNESIUM HYDROXIDE. SIMILARLY OXIDES OF POTASSIUM AND SODIUM FORM POTASSIUM HYDROXIDE AND SODIUM HYDROXIDE WHEN DISSOLVED IN WATER. ALL THESE ARE BASIC IN NATURE. THEY WOULD BE SOAPY WHEN TOUCHED.