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प्रश्न
Phenolphthalein is a synthetic type of indicator.
पर्याय
True
False
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उत्तर
Phenolphthalein is a synthetic type of indicator - True
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संबंधित प्रश्न
10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:
Complete and balance the following chemical equation:
\[\ce{CuO_{(s)} + HCl_{(aq)} ->}\]
What happens when an acid reacts with a metal? Give the chemical equation of the reaction involved.
What happens when an acid reacts with a base? Explain by taking the example of hydrochloric acid and sodium hydroxide. Give equation of the chemical reaction which takes place. What is the special name of such a reaction?
A first-aid manual suggests that vinegar should be used to treat wasp stings and baking soda for bee stings. What does this information tell you about the chemical nature of:
wasp stings?
A first-aid manual suggests that vinegar should be used to treat wasp stings and baking soda for bee stings. What does this information tell you about the chemical nature of:
bee stings?
State two uses each of the following compounds:
Sodium hydroxide
What are esters? How are esters prepared? Write the chemical equation for the reaction involved. What happens when an ester reacts with sodium hydroxide? Write the chemical equation for the reaction and also state the name and use of this reaction.
With the help of suitable examples explain the term neutralization and the formation of –
- acidic,
- basic and
- neutral salts
A student added 10 g of calcium carbonate in a rigid container, secured it tightly and started to heat it. After some time, an increase in pressure was observed, the pressure reading was then noted at intervals of 5 mins and plotted against time, in a graph as shown below. During which time interval did maximum decomposition take place?
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?
In the following schematic diagram for the preparation of hydrogen gas as shown in the figure, what would happen if following changes are made?
- In place of zinc granules, same amount of zinc dust is taken in the test tube
- Instead of dilute sulphuric acid, dilute hydrochloric acid is taken
- In place of zinc, copper turnings are taken
- Sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated.
A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance which can be moulded into different shapes by making its dough. When this compound is left in open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt. Why does it show such a behaviour? Give the reaction involved.
Take a clean test tube with a holder and pour some dilute hydrochloric acid. Add a few pieces of magnesium ribbon pieces slowly. What do you observe? Now show a burning match stick near the mouth of the test tube. Do you hear any sound? The gas burns with a pop sound. From this, it is observed that hydrogen gas has been formed due to the reaction between acid and metal.
“All acids contain one or more hydrogen atoms, but not all substances containing hydrogen are acids.” Support this statement with examples.
The taste of acid is ______.
On placing a copper coin in a test tube containing green ferrous sulphate solution, it will be observed that the ferrous sulphate solution ______.
A substance 'X' is used as a building material and is insoluble in water. When it reacts with dil. HCl, it produces a gas which turns lime water milky.
- Write the chemical name and formula of 'X'.
- Write chemical equations for the chemical reactions involved in the above statements.
The metal that will not produce hydrogen gas when reacted with dilute acids.
