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प्रश्न
The valency of calcium is 2. Write the valencies of other radical in the following :
- CaO
- Ca(OH)2
- CaC03
- CaCl2
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उत्तर
- O= 2
- OH = 1
- CO3 = 2
- Cl = l
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संबंधित प्रश्न
Name the following radicals :
OH
A liquid compound X of molecular mass 18 u can be obtained from a number of natural sources. All the animals and plants need liquid X for their survival. When an electric current is passed through 200 grams of pure liquid X under suitable conditions, then 178 grams of gas Y and 22 grams of gas Z are produced. Gas Y is produced at the positive electrode whereas gas Z is obtained at the negative electrode. Moreover, gas Y supports combustion whereas gas Z burns itself causing explosions.
- Name (i) liquid X (ii) gas Y, and (iii) gas Z.
- What is the ratio of the mass of element Z to the mass of element Y in the liquid X ?
- Which law of chemical combination is illustrated by this example ?
- Name two sources of liquid X.
- State an important use of Y in our life.
State whether the following statements are true or false:
A sodium ion has positive charge because it has more protons than a neutral atom.
An element X has a valency of 2. Write the simplest formula for oxide of the element.
The valencies (or charges) of some of the ions are given below :
| Ion | Valency (Charge) | Ion | Valency (Charge) |
| Sodium ion | 1+ | Bromide ion | 1– |
| Ammonium ion | 1+ | Hydroxide ion | 1– |
| Calcium ion | 2+ | Sulphate ion | 2– |
| Lead ion | 2+ | Phosphate ion | 3– |
Using this information, write down the formulae of the following compounds :
(i) Sodium phosphate
(ii) Ammonium sulphate
(iii) Calcium hydroxide
(iv) Lead bromide
Write symbols of the following elements and the radicals obtained from them and indicate the charge on the radicals.
Mercury, potassium, nitrogen, copper, sulphur, carbon, chlorine, oxygen
Write the basic radicals and acidic radicals of the following and then write the chemical formulae of these compound.
Chromium sulphate
Write the basic radicals and acidic radicals of the following and then write the chemical formulae of these compound.
Potassium manganate
Complete the following table.
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Acid Radicals `→` |
Chloride |
Nitrate |
Sulphate |
Carbonate |
Hydroxide |
Phosphate |
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Basic Radicals `↓` |
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Magnesium |
MgCl2 |
Mg(NO3)2 |
MgSO4 |
MgCO3 |
Mg(OH)2 |
Mg3(PO4)2 |
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Sodium |
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Zinc |
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Silver |
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Ammonium |
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Calcium |
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Iron (II) |
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Potassium |
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State if the following element or radical is divalent?
Nickel
