Acids, Bases and Salts — Science STD 10 — Question

The discomfort caused by indigestion due to overeating can be cured by taking:

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that:

Consider the following statements related to diamond and graphite.

1. Both diamond and graphite are used as abrasives.
2. Diamond and graphite have different arrangements of carbon atoms.
3. The carbon atoms in graphite have a different number of neutrons from those in diamond.
4. The carbon atoms in both graphite and diamond have four single covalent bonds. The incorrect statement(s) is/are.

Aqueous solutions of zinc sulphate and iron sulphate were taken in test tubes I and II by four students A,  B,  C and D . Metal pieces of iron and zinc were dropped in the two solutions and observations made after several hours were recorded in the form of table as given below:

The correct reporting has been made in observations:

A student adds 2mL of acetic acid to a test tube containing 2mL of distilled water. He then shakes the test tube well and leaves it to settle for some time. After about 5 minutes he observes that in the test tube there is:

Which among the following statement(s) is (are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to:

1. The formation of silver by decomposition of silver chloride.
2. Sublimation of silver chloride.
3. Decomposition of chlorine gas from silver chloride.
4. Oxidation of silver chloride.

1. 1 Only
2. 1 and 3
3. 2 and 3
4. Only 4

The number of carbon atoms present in the molecule of fifth member of the homologous series of alkynes is:

1. Four.
2. Five.
3. Six.
4. Seven.