Questions

Lala Lajpat Rai, popularly known as Punjab Kesari was an Indian Freedom Fighter who gave the safety valve theory for Indian National Congress in 1916 in a daily news paper paper 'Young India'. 

It was said that the INC was started by Viceroy Lord Dufferin with the help of an ex Civil Services member as a 'Safety Valve' against the popular discontent.

The eye can see images separately only if they are exhibited at an interval of more than 1/10 of a second. In the case of a movie, the still pictures come one after the other at less than this minimum interval. So we do not see them separately but only as a continuous moving picture.

Tetraethyl lead is a highly toxic compound used as a gasoline additive.

Tetraethyl lead abbreviated as TEL, is an organo lead compound with the formula (CH₃CH₂)₄Pb. It is a petro-fuel additive which in turn caused increased vehicle performance. This is also used as an antiknock agent in gasoline and jet fuels. Tetraethyl lead is absorbed rapidly by the skin, the lungs, and the gastrointestinal tract. It is converted to triethyl lead, which might be responsible for its toxicity.

Washing soda is the common name for Sodium Carbonate (Na2CO3). It is also called as Soda Ash.

A metalloid is an element with properties between metals and non metals or the mix of both.

The six metalloids are arsenic, silicon, germanium, boron, antimony and tellurium.

Hence, silicon is the only metalloid in the given list.