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:
1.Lemon juice
2.Vinegar
3.Common salt
4. An antacid
Posted Date:-2021-12-18 10:27:42
A student noted his observations regarding the acidic or basic nature of salts as below: (I) Sodium chloride is a neutral salt (II) Ammonium chloride is a basic salt (III) Sodium carbonate is a neutral salt (IV) Copper sulphate is an acidic salt Select the incorrect observations:
1.Both (I) and (III) (b) (c) (d)
2.Both (II) and (III)
3.Both (I) and (IV)
4.Both (II) and (IV)
Posted Date:-2021-12-18 10:36:49
A visually challenged student has to perform a lab test to detect the presence of acid in a given solution. The acid-base indicator preferred by him will be:
1. Blue litmus
2.Clove oil
3.Red cabbage extract
4.Hibiscus extract
Posted Date:-2021-12-18 10:22:50
Acids and bases represent two important classes of chemical compounds. In every day life, acids and bases play a role in everything from the digestion of the foods you eat to the function of the medicine you take and even the cleaning products you use. Without acids and bases, many of the products in your home today would not have much use. Acids and bases are also important in atmospheric, geological, and physiological processes because they have unique chemical properties. Acids and bases have unique chemical properties because of the atomic composition of these compounds and how these compounds interact with other atoms and molecules. The pH of some common substances is shown below:
1.The nature of calcium phosphate present in tooth enamel is:
2.Basic
3.Amphoteric
4.Acidic
Posted Date:-2021-12-18 10:54:35
Alloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contains non-metal as one of its constituents?
1.Brass
2.Bronze
3.Amalgam
4.Steel
Posted Date:-2021-12-18 11:28:41
An electrolytic cell consists of: (I) Positively charged cathode (II) Negatively charged anode (III) Positively charged anode (IV) Negatively charged cathode
1. (I) and (II)
2.(III) and (IV)
3.(I) and (III)
4.(II) and (IV)
Posted Date:-2021-12-18 11:27:52
An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept ¡n open air. It reacts vigorously with water. Identify the element from the following:
1.Mg
2.Na
3.P
4.Co
Posted Date:-2021-12-18 11:12:30
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of:
1. Gallium
2.Aluminium
3.Zinc
4.Silver
Posted Date:-2021-12-18 11:25:34
Generally, metals are soLid in nature. Which one of the following metals is found in Liquid state at room temperature?
1.Na
2.Fe
3.Cr
4.Hg
Posted Date:-2021-12-18 11:32:08
Generally, non-metals are not Lustrous. Which of the following non-metals is lustrous?
1.Sulphur
2.Oxygen
3.Nitrogen
4.Iodine
Posted Date:-2021-12-18 10:59:38
If 10 mL of H2SO4 is mixed with 10 mL of Mg(OH)2 of the same concentration, the resultant solution will give the following colour with a universal indicator:
1.Red
2.Yellow
3.Green
4.Blue
Posted Date:-2021-12-18 10:16:54
Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining? (I) Au (II) Cu (III) Na (IV) K
1.(I) and (II)
2.(IV) and (III)
3.(II) and (III)
4. (II) and (IV)
Posted Date:-2021-12-18 11:24:45
Neetu’s friend suffered a fracture in her foot while riding her bicycle. She had to be admitted to the nursing home and the doctor plastered her foot. The chemical formula for Plaster of Paris is:
1.CaSO4.2H2O
2.CaSO4.H2O
3.CaSO4.12H2O
4.2CaSO4.H2O
Posted Date:-2021-12-18 10:44:19
Sandhya took three beakers A, B and C containing zinc sulphate, silver sulphate and iron(ll) sulphate solutions respectively. Copper pieces were added to each beaker. The solution will appear blue in the case of:
1.Beaker A
2.Beaker B
3.Beaker C
4.Beakers B and C [Diksha]
Posted Date:-2021-12-18 11:22:43
Sodium hydrogen carbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved? (I) It turns lime water milky. (II) It extinguishes a burning splinter. (III) It dissolves in a solution of sodium hydroxide. (IV) It has a pungent odour.
1.(I) and (II)
2.(I), (II) and (III)
3.(II), (III) and (IV)
4.(I) and (IV)
Posted Date:-2021-12-18 10:23:53
Stainless steel is a very useful material in our life, in stainless steel, iron is mixed with:
1.Mi and Cr
2.Cu and Cr
3.Mi and Cu
4.Cu and Au
Posted Date:-2021-12-18 11:26:49
Take about 2 mL of dilute NaOH solution in a test tube and a small amount of copper oxide in a beaker. Add two drops of phenolphthalein solution in the test tube. Add dilute HCl solution in both the test tube and the beaker drop by drop while stirring. Now add a few drops of NaOH to the mixture in the test tube
1.The solution turns pink in colour
2.The solution turns colourless
3.The solution turns red
4.The solution turns yellow
Posted Date:-2021-12-18 10:48:15
To protect against tooth decay we are advised to brush our teeth regularly. The nature of the toothpaste commonly used is:
1.Acidic
2.Neutral
3.Basic
4.Corrosive
Posted Date:-2021-12-18 10:24:42
What happens when calcium is treated with water? (I) It does not react with water. (II) It reacts violently with water. (III) It reacts Less violently with water. (IV) Bubbles of hydrogen gas formed stick to the surface of calcium.
1.(I) and (IV)
2.(II) and (III)
3.(I) and (II)
4.(III) and (IV)
Posted Date:-2021-12-18 10:57:45
What happens when the solution of an acid is mixed with the solution of a base in a test tube?
1.The temperature of the solution increases
2.The temperature of the solution decreases
3.The temperature of the solution remains the same
4. Salt formation takes place
Posted Date:-2021-12-18 10:15:55
When we smile, our teeth become visible. So, we should ensure that we have a beautiful set of teeth as it makes our smile even more beautiful! Tooth enamel is the thin outer covering of the tooth. This tough shell is the hardest tissue in the human body. Enamel covers the crown which is the part of the tooth that’s visible outside of the gums. Calcium phosphate is present in tooth enamel. Its nature is:
1.Basic
2.Acidic
3.Neutral
4.Amphoteric
Posted Date:-2021-12-18 10:42:52
Which among the following is not a base?
1.NaOH
2.KOH
3.NH4OH
4.C2H5OH
Posted Date:-2021-12-18 10:30:41
Which metal can be displaced by copper from Its salt solution? (I) Silver (II) Magnesium (III) iron (IV) Iron Correct options are:
1.(I) and (II)
2.(I) and (III)
3.(II) and (III)
4. (I) and (IV)
Posted Date:-2021-12-18 11:24:00
Which of the following is/are true when HCl(g) is passed through water? (I) It does not ionise in the solution as it is a covalent compound. (II) It ionises in the solution. (III) It gives both hydrogen and hydroxyl ions in the solution. (IV) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule.
1.Only (I)
2.Only (III)
3.(II) and (IV)
4.(III) and (IV)
Posted Date:-2021-12-18 10:29:56
Which of the following oxide(s) of iron would be obtained on the prolonged reaction of iron with steam?
1.FeO
2.Fe2O3
3.Fe3O4
4.Fe2O3 and Fe3O4
Posted Date:-2021-12-18 10:56:50
Which of the following properties is generally not shown by metals?
1.Electrical conduction
2.Sonorous in nature
3.Dullness
4.Ductility
Posted Date:-2021-12-18 10:55:49
Which of the following solutions in water does not conduct electricity?
1.Hydrochloric acid
2.Sodium chloride
3.Glucose
4.Sulphuric acid [Diksha]
Posted Date:-2021-12-18 10:33:07
Which one of the following is not a use of washing soda:
1.Sodium carbonate (washing soda) is used in glass, soap and paper industries.
2.It is used in the manufacture of sodium compounds such as borax.
3.Sodium carbonate can be used as a clean¬ing agent for domestic purposes.
4.It is used for disinfecting water.
Posted Date:-2021-12-18 10:34:30
While performing experiments in chemistry lab, one should always wear a laboratory coat and be very careful while performing experiments. Some students have the bad habit of creating nuisance for other students which distracts the students and may cause serious accidents such as spilling of acid or can cause burn injuries. If a few drops of concentrated acid accidentally spills over the hand of a student, what should be done?
1.Wash the hand with a saline solution
2.Wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonate
3.After washing with plenty of water, apply a solution of sodium hydroxide on the hand
4.Neutralise the acid with a strong alkali
Posted Date:-2021-12-18 10:46:07
Zinc granules on treating with an acid X, form zinc sulphate (ZnSO4) salt along with the evolution of a gas Y, which burns with a pop sound when brought near to a burning candle. Identify acid X and gas evolved Y.
1.X-sulphuric acid and Y-oxygen gas
2.X-hydrochloric acid and Y-oxygen gas
3. X-sulphuric acid and Y-hydrogen gas
4.X-hydrochloric acid and Y-hydrogen gas [Diksha]
Posted Date:-2021-12-18 10:31:38