The metallic constituents of hard water are
Calcium, magnesium and iron
Magnesium, Calcium and tin
Magnesium, tin and iron
Iron, tin and calcium
- Which of the following elements is obtained from sea weeds ?
- In an atomic nucleus, neutrons and protons are held together by
- Apparatus invented by Archimedes is :
- The most important ore of Aluminium is
- Earth's seasons are caused by which of the following?
- Permanent hardness of water, due to sulphates of the metal, can be destroyed by the use of
- The colour of Emerald is
- Which of the following is in liquid form at room temperature ?
- Glass is made from the mixture of
- Brass gets discoloured in air due to the presence of which gas in air
- The oxide of Nitrogen used in medicine as anaesthetic is
- The metal that is present in Photo Films is
- Which of the following items will be attracted to the north pole of a permanent magnet by a magnet force?
- What is the unit for measuring the pitch or frequency of sound ?
- Water has maximum density at
- The element present in the largest amount in rocks and minerals is
- The Panda belongs to the same family as that of
- The metal used in storage batteries
- Polythene is industrially prepared by the polymerisation of
- The type of glass used in making prisms and lenses is
- Which of the following elements is non-radioactive?
- The recent atomic weight scale is based on
- The metallic constituents of hard water are
- The fastest acting enzyme in the biological kingdom is
- Carbon tetrachloride fire extinguisher should not be used in closed room because it produces poisonous…
- The formula of Plaster of Paris is
- The speed of light with the rise in the temperature of the medium
- Which of the following is commonly called a polyamide ?
- The accumulation of stress along the boundaries of lithospheric plates results in which of the following?
- The property of a substance to absorb moisture from the air on exposure is called