Q1. Curd making is an ancient “Biotechnological” process involving: –
Sol. When pasteurized milk is heated to a temperature of 30-40°C or even at room temperature and a small amount of old curd or whey is added to it, the lactobacillus in that curd or whey sample starts to grow. They convert the lactose into lactic acid, which imparts the sour taste to curd.
Q2. Which of the following oil is an extract of clove oil?
Sol. Eugenol is a colourless or light yellow oil extract from clove oil . It smells like cloves with spicy pungent taste.
Q3. Organic food is supposed to be better for us because it
(a) Relies on chemicals to improve the flavour
(b) Is more expensive to buy
(c) Is grown in glasshouses keeping it clean of environmental pollutants.
(d) Is grown without the use of artificial fertilizers and pesticides.
Sol. Organic food is produced by farmers who emphasize the use of renewable resources and the conservation of soil and water to enhance environmental quality for future generations. The organic food is produced without using most conventional pesticides; fertilizers made with synthetic ingredients or sewage sludge, bioengineering or ionizing radiation.
Q4. Balloons are filled with
Sol. Balloons are filled with Helium.
Q5. Which of the following is not a chemical fertilizer?
(b) Sodium Sulphate
(c) Super Phosphate
(d) Potassium Nitrate
Sol. Urea, superphosphate and Potassium Nitrate are chemical fertilizers. Sodium Sulphate is the sodium salt of Sulphuric acid. Sodium Sulphate is not used as a chemical fertilizer.
Q6. The softest mineral, Talc (Soapstone) is mainly: .
(a) Manganese Silicate
(b) Sodium Silicate
(c) Sodium Phosphate
(d) Magnesium Silicate
Sol. Talc is a mineral which is composed of hydrated Magnesium silicate
Q7. To make the steel hard requires increase in-
(a) The quantity of Carbon
(b) The quantity of Manganese
(c) The quantity of Silicon
(d) The quantity of Chromium
Sol. Steels are alloys of Iron and other elements primarily Carbon and are widely used in construction and other area. Carbon inclusion in Iron as a hardening agent which strengthens Iron by distorting its crystal lattice. This distortion result in hardening.
Q8. The highest amount of carbon is in-
(a) Pig Iron
(b) Wrought Iron
(d) Alloy Steel
Sol. Pig Iron has a very high Carbon content, typically 3.5–4.5%. Wrought Iron is an Iron alloy with a very low Carbon (less than 0.08%) content. Steels containing 0.2% to 1.5% Carbon are known as Carbon steel. The amount of Carbon in alloy steel ranges from 0.1% to 1%.
Q9. Which of the following is not in the form of crystal?
(d) None of these
Sol. Salt, Sugar, Diamond, Quartz. Ice, Graphite etc. All are in the formed crystal.
Q10. Burning of Hydrogen produces-
Sol. Hydrogen gas is highly flammable and burns in air at a very wide range of concentrations between 4% to 75% by volume. Hydrogen gas cannot burn in absence of air. But by burning with Oxygen it produces water.