OMTEX CLASSES
Q1. A. Fill in the blanks.
1. ____group in the periodic table contains elements that are all gases at room temperature.
2. The law used by Newlands to arrange elements is known as_______.
3. Elements showing properties of both metals and non – metals are known as________.
4. The chemical reaction during which H2(g) is lost is termed as______.
5. When acids and alkalis react together, salt and ______are formed.
6. Most of the acidic substances are _____in taste.
7. The strength of basic substance is represented by_____.
8. Acids and bases neutralize each other to form _______and______.
9. In FeSO4. 7H2O.H2O represents______________.
10. Litmus paper or solution is obtained from a plant named________.
Q2. Write short notes on
1. Indicators (with proper example).
2. pH scale (with proper diagram).
Q3. Answer the following questions.
1. What is universal indicator? Does Mg(OH)2 react with sodium hydroxide? If not, why?
2. How could the modern periodic table remove various anomalies of Mendeleev’s periodic table?
3. What are the demerits of Mendeleev’s periodic table?
Q4. Give Scientific reasons.
1. Grills of doors and windows are always painted before they are used.
2. Potassium Ferrocyanide is stored in dark coloured bottles and kept away from sunlight.
3. Edible oil is not allowed to stand for a long time in an iron or tin container.
4. Atomic size increases down the group.