Which element is blue in liquid state?
hydrogen
nitrogen
oxygen
helium
Liquid oxygen has a pale blue color and is strongly paramagnetic.  The first measurable quantity of liquid oxygen was produced by Polish professors Zygmunt Wróblewski and Karol Olszewski (Jagiellonian University in Kraków) on April 5, 1883.  
reach: rather globalchemical elementschemistryscience
Answers by country
hydrogen
nitrogen
oxygen
helium
answers
 the Netherlands
the Netherlands16
 France
France18
 Australia
Australia84
 Poland
Poland3188
 Canada
Canada33
 the United States
the United States305
 Germany
Germany524
 Malaysia
Malaysia16
 Austria
Austria87
 Vietnam
Vietnam14
 the United Kingdom
the United Kingdom178
 Greece
Greece21
 Switzerland
Switzerland38
 India
India533
 Republic of Ireland
Republic of Ireland16
 Ghana
Ghana30
 Nigeria
Nigeria118
 the Philippines
the Philippines46
 Singapore
Singapore20
 Pakistan
Pakistan53