Why should curd and sour substances not be kept in brass and copper vessels?

Consider the following:

1. Tomato - Citric acid
2. Sour milk - Lactic acid
3. Vinegar - Methanoic acid

Which of the above-mentioned pairs is/are correctly matched?

Consider the following statements: If there were no phenomenon of capillarity: 

1. It would be difficult to use a kerosene lamp.
2. One would not be able to use a straw to consume a soft drink.
3. The blotting paper would fail to function.
4. The big trees that we see around would not have grown on the Earth.

Which of the statements given above are correct?

Which of the following statements is/are INCORRECT?

1. A sugar solution is a homogenous mixture.
2. Both homogenous and heterogeneous mixtures can be separated through physical methods only.
3. Compounds can be separated through chemical methods but not through physical methods.

Select the correct answer using the code given below:

Which of the following is/are an example of corrosion?

1. Copper reacts with moist carbon dioxide in the air.
2. Silver articles when exposed to air.
3. Iron when exposed to moist air.

Select the correct answer from the code given below: