(d) Sodium silicate
Ans: (b)
130. The chemical substance which is easily soluble in water is [UPPCS (Pre) 1993]
         (a) carbon
         (b) nitrogen
         (c) ammonia
         (d) iodine
Ans: (c)
131. Before X-ray examination (coloured X-ray) of the stomach, pateints are given suitable salt of barium because-
         (a) Barium salts are white in colour and this helps stomach to appear clearly
         (b) Barium is a good absorber of X-rays and helps stomach to appear clearly
         (c) Barium salts are easily available
         (d) Barium allows X-rays to pass through the stomach
Ans: (b)
132. Tear gas is : [Uttarakhand PCS 2003]
         (a) hydrogen sulphide
         (b) chlorine
         (c) hydrogen chloride
         (d) ammonia
Ans: (b)
133. The most abundantly occurring element in the earth-crust is : [BPSC (Pre) 1998]
         (a) oxygen
         (b) nitrogen
         (c) manganese
         (d) silicon
Ans: (a)
134. Which one among the following polymers is used for making bullet proof material? [CDS, 2012]
         (a) Polyvinyl Chloride
         (b) Polystyrene
         (c) Polyethylene
         (d) Polyamide
Ans: (b)
135. Oxygen and Ozone are: [CDS, 2012]
         (a) allotropes
         (b) isotopes
         (c) isomers
         (d) isobars
Ans: (a)
136. Which one of the following is not a mixture? [COS, 2010]
         (a) Toothpaste
         (b) Toilet soap
         (c) Baking soda
         (d) Vinegar
Ans: (c)
137. Which one of the following is the correct sequence of the reactivity order of the elements? [NDA 2010]
         (a) Cu > Mg > Zn > Na
         (b) Na > Zn > Mg > Cu
         (c) Cu > Zn > Mg > Na
         (d) Na > Mg > Zn > Cu
Ans: (b)
138. Which of the following is assumed to be the most fundamental chemical in the chemical industry? [BPSC (Pre)
         (a) H2CO3
         (b) HNO3
         (c) H2SO4
         (d) HCI
Ans: (c)
139. The electrolyte used in the car battery is: [BPSC (Pre) 1998]
         (a) hydrochloric acid
         (b) sulphuric acid
         (c) nitric acid